2027 Chevrolet Colorado and GMC Canyon: 350-HP TurboMax, the Returning Desert Boss, and What GM Has Not Published

GM’s mid-size pickups gain 40 horsepower and keep every tow rating they had. The 2027 Chevrolet Colorado and its GMC Canyon twin move from the 310-hp L3B to the enhanced 2.7-liter L4B TurboMax, rated 350 horsepower and 455 lb-ft, retain an updated eight-speed automatic rather than the ten-speed used in the full-size trucks, and carry unchanged maximum tow ratings of 7,700 pounds for standard trucks, 6,000 pounds for ZR2 and AT4X, and 5,500 pounds for Bison and AEV Editions. Production is scheduled to begin in fall 2026 at GM’s Wentzville Assembly in Missouri. Separately, and reported three weeks after the engine story, the ZR2 Desert Boss name returns for 2027 as a dealer-installed package that is reported to include a lighting package.

Two things about that opening paragraph deserve emphasis, because most of the coverage so far has blurred them. The engine change is documented in dealer order guides and reported by trade media rather than announced in a Chevrolet press release, and the Desert Boss return is reported second-hand from an order-guide specialist by a general-interest outlet. Neither is a rumor in the sense of an unsourced forum post, but neither is a GM press kit either. This article separates what GM has published from what dealers’ order guides show from what nobody has confirmed, and then does the part that matters for anyone who plans to bolt lights onto one of these trucks: it works out what the change does and does not alter about the electrical, thermal and legal envelope around the vehicle.

Quick answer: what changed on the 2027 Colorado and Canyon

Four things change, and three things do not.

The changes: the engine becomes the L4B TurboMax at 350 hp and 455 lb-ft; the 2027 Colorado adds exterior colors, a power-adjustable front passenger seat and what AutoGuide describes as minor equipment revisions for the ZR2; the 2027 Canyon adds new wheel designs, expanded interior connectivity and updated trim options; and the ZR2 Desert Boss returns as a dealer-installed package reported to include a distinctive lighting package.

The non-changes matter just as much. The transmission stays an eight-speed automatic, a point AutoGuide makes explicitly by describing it as an updated version of the existing unit, in contrast with the ten-speed that the full-size 2027 Silverado 1500 and Sierra 1500 use behind the same engine family. The tow ratings do not move. And no lighting specification, in the sense a lighting engineer would accept the word, has been published for either truck.

For a buyer, the practical reading is that the 2027 mid-size trucks are a powertrain update with a cosmetic and equipment refresh, not a new platform. For an owner planning auxiliary lighting, it means the truck you are wiring is the same body, the same bed, the same electrical architecture and the same lamp locations as the 2023-2026 truck, with a different engine calibration and, if you order the ZR2, an additional dealer-fitted accessory package whose lamp content is currently unknown.

Confirmed, reported and unconfirmed: three tiers you must keep apart

Every claim in this article sits in one of three tiers, and the tiers are not interchangeable. Conflating them is how a dealer-installed accessory becomes “factory standard” in a forum thread, and how a 450 lb-ft figure propagates through a dozen aggregators.

Tier	What it means	Examples in this story
Published by GM	Appears in an official GM document, with a date and a footnote set	2.7L TurboMax rated 350 hp at 5,200 rpm and 455 lb-ft at 3,000 rpm; bore and stroke 3.63 x 4.01 in; DOHC four-valve heads with variable valve lift; 10-speed automatic in the 2027 Silverado 1500; 9,400 lb maximum trailering for that truck
Reported from order guides	Documented in dealer ordering material, relayed by trade media, not announced in a press release	The L4B replacing the L3B in Colorado and Canyon; the eight-speed automatic being retained; unchanged tow ratings of 7,700 / 6,000 / 5,500 lb; fall 2026 production at Wentzville; the 2027 color, seat, wheel and connectivity changes
Reported second-hand, unconfirmed by GM	Traced to a specialist outlet’s order-guide reporting and then relayed by a general outlet	The Desert Boss Special Edition; its ZR2-only availability; the dealer-installed status; the package contents including the lighting package; the exclusion from Bison and Midnight packages

The third tier is the one to handle with care, and not because it is likely to be wrong. It is the tier where detail is thinnest. A report that a package includes “a distinctive lighting package” tells you that lamps are part of the kit. It does not tell you how many lamps, of what type, at what output, switched how, fused where, or whether a roof bar is among them.

The L4B TurboMax: 350 hp and 455 lb-ft, and where those numbers come from

The L4B is not a new engine in the sense of a clean-sheet design. It is the enhanced version of the 2.7-liter turbocharged inline-four that GM has been building for years, and its output figures are published, in an official GM specification table, for the 2027 Silverado 1500. That table gives 350 hp at 5,200 rpm and 455 lb-ft at 3,000 rpm, with a 3.63 in bore and 4.01 in stroke (92.25 mm by 102 mm), a cast aluminum block with cast iron liners, dual overhead camshafts with four valves per cylinder, continuously variable valve timing, variable valve lift, Active Fuel Management and direct injection.

AutoGuide’s report on the mid-size trucks names the hardware changed to get there: a re-engineered turbocharger, redesigned pistons, upgraded fuel injection, revised active thermal management, and hardware tweaks aimed at reducing noise, vibration and harshness. The outlet also states that the upgraded 2.7-liter four is the same base engine going into the updated full-size trucks, which is consistent with one engine family rather than two.

Specification	L3B (outgoing)	L4B TurboMax (2027)	Source
Displacement	2.7 L turbocharged inline-four	2.7 L turbocharged inline-four	AutoGuide; GM
Horsepower	310 hp	350 hp at 5,200 rpm	AutoGuide; GM
Torque	430 lb-ft	455 lb-ft at 3,000 rpm	CarScoops; GM
Bore x stroke	Not published in the sources used here	3.63 x 4.01 in (92.25 x 102 mm)	GM
Valvetrain	Not published in the sources used here	DOHC, four valves per cylinder, CVVT, variable valve lift, AFM	GM
Fuel delivery	Not published in the sources used here	Direct injection	GM
Transmission, mid-size	Eight-speed automatic	Updated eight-speed automatic	AutoGuide
Transmission, full-size	Not applicable	Ten-speed automatic	GM; Business Fleet

One number in that table is contested. AutoGuide gives 455 lb-ft; GM’s table for the same engine family gives 455 lb-ft; Business Fleet repeats 455 lb-ft. CarScoops, writing about the Desert Boss on 14 October 2026, states 450 lb-ft. Three sources against one, two traceable to GM’s own table, makes 455 lb-ft the figure to quote. The accurate statement, though, is narrower: the 2027 Chevrolet Colorado uses the L4B, the L4B is rated 350 hp and 455 lb-ft in GM’s 2027 full-size specification table, and a mid-size-specific rating has not been published. A different intake, exhaust, cooling package or emissions route can shift a rating by a few lb-ft without touching the internals, which is why the distinction is worth keeping.

Why the eight-speed automatic stays while the full-size trucks move to ten speeds

This is the single most consequential detail in the whole update for anyone who tows, and it is easy to miss because it is a negative: the mid-size trucks do not get the ten-speed.

The full-size story is unambiguous. GM’s June 2026 release describes the enhanced 2.7L TurboMax as “now paired with a 10-speed transmission,” and Business Fleet’s September 2026 summary states that all four 2027 full-size powertrains, the TurboMax, the 3.0L Duramax and both new V8s, are paired with a ten-speed automatic. The mid-size story, per AutoGuide, is that Colorado and Canyon “will retain an updated version of their existing eight-speed automatic.”

Gear count is not a proxy for quality, and an eight-speed that has been revised for a new torque curve is not automatically worse than a ten-speed. What gear count does affect is the spread of ratios available for a given road speed, which in turn affects downshift behaviour under load, engine braking on a descent, and the resolution with which the truck can hold a tall gear at highway speed. Those are exactly the conditions where an owner notices a transmission: a loaded truck on a grade, a trailer on a long descent, a headwind at 70 mph.

There is a second-order effect that matters here. Engine and transmission calibration determine how long the engine spends at high load, which determines how much heat is rejected into the engine bay. A bay that runs hotter under sustained load is a bay where a relay box, fuse holder or lamp driver mounted in the wrong place ages faster. The response is not to speculate about unpublished numbers; it is to mount electrical hardware away from exhaust and radiator discharge, and to test for it.

Towing and payload: the ratings that did not move

AutoGuide reports that despite the power increase, towing limits remain unchanged across the lineup, and gives the three figures that matter.

Configuration	Maximum tow rating	Change for 2027
Standard Colorado and Canyon	7,700 lb	Unchanged
Colorado ZR2 and Canyon AT4X	6,000 lb	Unchanged
Colorado ZR2 Bison and Canyon AT4X AEV Edition	5,500 lb	Unchanged

A power increase with no tow-rating increase is not a contradiction. Tow ratings are set by the weakest link in a chain that includes frame stiffness, hitch structure, cooling capacity, transmission and axle durability, and brake capability, and 40 hp addresses one link of it. The same logic governs auxiliary lighting: the engine is never the limiting component in a lamp circuit.

The payload side matters more for work-truck buyers, and the numbers that circulate here are full-size figures, not mid-size ones. GM’s specification table for the 2027 Silverado 1500 lists a maximum payload of 2,340 lb for the Enhanced TurboMax in a regular cab, standard box, two-wheel-drive configuration, and Business Fleet gives 2,340 lb for the Silverado and 2,310 lb for the Sierra. None of those transfers to a Colorado or Canyon, whose payload GM has not published for 2027 in the sources used here.

Payload is what bites an owner who adds accessories, because every bracket, bar, lamp and drawer set comes out of it. A roof light bar is not heavy in absolute terms, but it sits high, which is the worst place to add mass for roll behaviour, and it cantilevers off a roof panel that is not a load-bearing accessory platform on most mid-size trucks. That is a mounting question before it is a lighting question.

The ZR2 Desert Boss returns as a dealer-installed package

CarScoops reported on 14 October 2026 that Chevrolet will reintroduce the Desert Boss Special Edition on the 2027 Colorado ZR2, citing GM Authority. The 2023 original was a factory-prepped special edition; the 2027 version, according to that report, will be sold exclusively as a dealer-installed option.

That single word — dealer-installed — changes the ownership experience in ways that have nothing to do with how the truck looks.

Question	2023 Desert Boss	2027 Desert Boss (reported)
Factory-fitted or dealer-fitted	Factory-prepped special edition	Dealer-installed option
Which model	Colorado	Colorado ZR2 only
Package contents	Bull bar, roof-mounted light bar, rear sports bar, 17-inch wheels with 33-inch tires	Special off-road front bumper, a distinctive lighting package, Multimatic Jounce Control Dampers, Tech Bronze recovery hooks, door sill plates, front-fender decal package
Price	Added $9,295 to the sticker	Not announced
Combined with other packages	Not stated in the sources used here	Not offered with the Bison or Midnight packages

Dealer installation means the parts arrive as accessories and are fitted at the dealership rather than on the assembly line. In practice the work is documented on an accessory line on the buyer’s paperwork rather than in the vehicle’s as-built specification, availability depends on whether that dealer has the parts and the technician time, and warranty coverage runs through the accessory. Fit quality is a function of the individual technician, which is the argument for photographs and a signed work order before you accept the truck.

The report also explains why the package is ZR2-only. The Multimatic Jounce Control Dampers in the kit are nitrogen-charged hydraulic bump stops designed to work with Multimatic DSSV dampers, which are a $2,583 option on the Colorado ZR2 and standard on the ZR2 Bison. A jounce damper tuned to a specific damper is not a universal part, which is a plausible mechanical reason for restricting the package to the ZR2 and excluding the Bison, which already has the dampers as standard.

What the 2023 Desert Boss contained, and what the 2027 package is reported to contain

The 2023 kit is the useful reference point, because it is the only version whose contents have been described in any detail, and because one item in that list is a lamp.

CarScoops describes the 2023 package as including a bull bar, a roof-mounted light bar, a rear sports bar, and 17-inch wheels with 33-inch tires, and reports that it was discontinued after a year on sale.

The 2027 list is different in character. A special off-road front bumper replaces the bull bar, a “distinctive lighting package” appears where the roof-mounted light bar used to be named, and Jounce Control Dampers, Tech Bronze recovery hooks, door sill plates and a front-fender decal package round it out.

The difference between “a roof-mounted light bar” and “a distinctive lighting package” is the difference between a component and a category. A roof bar is one object with a mounting location, a housing, a beam pattern and a wiring route. A lighting package could be bumper pods, a grille bar, a roof bar, rock lights, a bed light or some combination, and the report does not say which.

Item	2023 (described)	2027 (reported)	What a buyer needs to ask
Front end	Bull bar	Special off-road front bumper	Does the bumper have lamp mounting points, and are they reinforced?
Lighting	Roof-mounted light bar	A distinctive lighting package	How many lamps, what type, what output, switched and fused how?
Suspension	Not listed	Multimatic Jounce Control Dampers	Are DSSV dampers included, or extra?
Rear, wheels and appearance	Sports bar, 17-inch wheels with 33-inch tires	Tech Bronze recovery hooks, door sill plates, fender decals	Does the package change wheel or tire specification at all?

A lighting package is only as good as its answers to those questions, and right now the answers do not exist in public.

What a factory-adjacent lighting package can and cannot promise you

A dealer-installed lighting package sits in an awkward category, and understanding the category prevents two opposite mistakes: assuming the lamps are “factory” and therefore beyond question, and assuming they are “aftermarket” and therefore suspect.

What such a package can legitimately promise is fit. If Chevrolet’s accessory engineers designed the brackets, the bumper has the mounting points, the harness is keyed to the truck’s connectors, and the switch is integrated into the interior, then the physical integration is likely to be better than a universal kit’s. That is a real advantage and it is the main reason people pay for accessory packages.

What it cannot promise, on the evidence available, is photometric performance. No output figure, no beam pattern description, no reference to an SAE or ECE photometric standard and no statement about road-use legality has been published for this package. A lamp being sold by a dealer does not make it legal to use on a public road in every mode, and a lamp being installed by a dealer does not make its beam pattern suitable for oncoming traffic. Those are separate questions, and the second one is the subject of the regulatory section below.

There is also an electrical question that a package price never answers. Accessory lighting adds load to a circuit that already carries the truck’s own lighting, and the correct way to add load is to give it its own fused, relay-switched feed from the battery rather than to tap an existing lamp circuit. Whether a dealer-installed package does that, or taps the factory fog-lamp circuit, is exactly the kind of detail that determines whether an owner has a trouble-free install or a truck that throws bulb-out warnings. It is not published, and it is worth asking about in writing before you sign. SAEC’s off-road lights category groups the lamp formats trucks most often use, which is a reasonable benchmark for what a package at that price should contain.

2027 Colorado and Canyon trims, read for night driving

The trim names in this story are worth pinning down, because each one carries a factual claim that affects what you can bolt on and what you are allowed to switch on.

Name	What the sources actually say	Why it matters for lighting
Colorado ZR2	One of the two trucks with a 6,000 lb tow rating; DSSV dampers are a $2,583 option on it; the Desert Boss package is reported to be ZR2-only	The Desert Boss lighting package, whatever it contains, is gated behind this trim
Colorado ZR2 Bison	5,500 lb tow rating; DSSV dampers standard; excluded from the Desert Boss package per the report	A buyer who wants both the dampers and the appearance package has to choose
Canyon AT4X	6,000 lb tow rating, the Canyon counterpart to the ZR2	Same tow figure, different body and bumper, so brackets do not transfer
Canyon AT4X AEV Edition	5,500 lb tow rating, the Canyon counterpart to the Bison	Same restriction logic as the Bison
Standard Colorado and Canyon	7,700 lb tow rating	The highest tow rating in the range

Two conclusions follow from that table. First, the tow rating you get is determined by the trim, not the engine, so the 40 hp increase does not change what any given truck can pull. Second, the trim that gets the reported lighting package also carries the lowest tow rating in the range, and it is the trim with the most off-road hardware, so it is the one where added accessory mass deserves the most thought before anything is bolted on.

Factory lighting on a mid-size GM truck: what is published and what is not

GM has not published a lighting specification for the 2027 Chevrolet Colorado or Canyon in any document used for this article: not the headlamp type, not the output, not the beam pattern, not the fog lamp configuration, not the bed lamp arrangement, not the trailer lamp circuit details.

What can be stated is what federal law requires the truck to have, because that part is public and it is the baseline an owner is modifying.

Question	What is established	Source
Must the headlamps be marked?	Yes. The lens of each original equipment and replacement headlamp must be marked with the symbol DOT	49 CFR 571.108, S6.5.1
Must other lamps be marked?	Not necessarily. Lamps other than headlamps may be marked DOT, and that mark is the manufacturer’s certification of conformity	49 CFR 571.108, S6.5.1.2
Can the truck have automatic daytime running lamps?	Yes, any pair of front lamps other than parking or fog lamps may be wired to activate automatically as DRLs	49 CFR 571.108, S6.1.1.4
Where must required lamps be mounted?	On a rigid, non-glazing part of the vehicle, within the position and height limits of Table I, and meeting photometry with obstructions considered	49 CFR 571.108, S6.1.3.1
What happens if equipment blocks a required lamp?	The vehicle must be equipped with an additional compliant lamp or device of the same type	49 CFR 571.108, S6.2.2

The practical consequence is that the truck arrives compliant, and every lamp added afterwards becomes the owner’s responsibility. That is not a loophole; it is the design of a self-certification system, and SAEC’s guide to DOT and E-Mark markings explains what such a mark does and does not prove about a lamp.

The 12-volt budget: worked arithmetic before you add a single lamp

A 350-hp truck still runs a 12-volt accessory system, and the arithmetic that governs an auxiliary lighting install is the same arithmetic that governed it when the truck had 310 hp. Horsepower does not appear in it.

Amps equal watts divided by volts. The calculation is done twice because a running alternator holds the system near 13.8 V while a circuit with the engine off sits nearer 12.0 V, and the lower figure produces the larger current for the same wattage. Sizing to the larger current is the conservative choice.

Lamp load	Current at 12.0 V	Current at 13.8 V
20 W	1.67 A	1.45 A
40 W	3.33 A	2.90 A
60 W	5.00 A	4.35 A
80 W	6.67 A	5.80 A
120 W	10.00 A	8.70 A
180 W	15.00 A	13.04 A
240 W	20.00 A	17.39 A

One caution: the wattage printed on a lamp box is not always the wattage the lamp draws. A lamp can pull more at 13.8 V than its label implies, and an inefficient driver turns some input into heat rather than light. Measure the actual current with a clamp meter on the finished install, then size fuse and wire for the measured figure plus margin.

Two 90 W pods are a 180 W load, 15.0 A at 12.0 V. That harness needs a fuse above 15.0 A, a relay rated above that current, a switch that carries only the coil current or is rated for the full load, and wire sized so voltage drop at the lamp stays small. SAEC’s wiring kit guide covers the selection method; the point here is that the calculation happens before the purchase, not after the first fuse blows.

Sizing the circuit: fuse, relay, switch and wire in the right order

The most common failure in an auxiliary lighting install is not a bad lamp. It is a circuit assembled in the wrong order, where the switch carries the lamp current, the fuse protects the lamp instead of the wire, and the ground return runs through a seat bolt.

Element	What it protects or controls	The mistake that causes failures
Battery feed	Supplies the load independently of the factory lamp circuits	Tapping an existing lamp circuit, which adds load to wiring sized for one lamp and can trigger bulb-out monitoring
Fuse	Protects the conductor, not the lamp	Fusing to the lamp’s nominal wattage, so the fuse is at the edge of normal draw and nuisance-blows on a cold night
Relay	Lets a low-current switch control a high-current load	Using a relay rated for the load but a socket rated for less, so the socket is the hot spot
Switch	Controls the relay coil, or the load if no relay is used	Putting a 15 A load through a 3 A switch, which welds the contacts closed
Wire	Carries current with acceptable voltage drop	Sizing for ampacity only, so a long run drops enough volts that the lamp is dim and the driver works harder
Ground	Completes the return path	Using a painted or corroded chassis point, which produces intermittent operation that looks like a lamp fault
Connector	Carries current across a service point	Using an unsealed connector in a wheel arch, which corrodes and raises resistance over one winter

Two rows are systematically underestimated. The ground return is half the circuit and the half most often improvised: a poor ground raises resistance, drops the voltage at the lamp and, in a constant-current driver, forces the driver to work harder and run hotter. The connector is where water gets in, so a sealed connector in a wheel arch is not a luxury on a truck that will see road salt.

Mounting positions on a Colorado or Canyon, compared

There are four realistic places to put auxiliary lamps on the 2027 Chevrolet Colorado or Canyon, and each carries consequences that have nothing to do with how the lamp performs on a test bench.

Position	Height above ground	Main advantage	Main problem	Wiring route
Front bumper, above the valance	Low	Close to the factory fog lamp location, short cable run, easy to aim against a wall	Exposed to road debris and to the first thing you hit; may obstruct a required lamp if placed carelessly	Short run to the engine bay, but through a high-splash zone
Behind the grille	Low to mid	Protected, visually discreet, good for a wide work pattern	Grille and shutter structures vary by trim, and the lamp sits behind plastic that was not designed as an optical window	Medium run, usually through the radiator support area
Roof, on a dedicated bar or rack	High	Long reach, no obstruction from the hood, useful for slow off-road work	Highest glare risk to other drivers and to your own hood; maximum structural and wind-load exposure; highest mounting point on the vehicle	Long run down a pillar, which needs a sealed penetration
Bed rack or sports bar	Mid to high	Good for work lighting around the truck and for load handling	Aimed away from the road, so useless for driving; adds mass at the highest point of the bed	Long run along the frame or through the bed side

Mounting height and aim determine who gets glare. A lamp mounted low and aimed down lights the road in front of you; the same lamp mounted high and aimed level puts light into the cab of the truck ahead. That is geometry, not lamp quality, and it is why one light bar can be sensible in one position and anti-social in another.

Structure follows the same logic. A roof bar loads the roof panel and the pillar, and on most mid-size trucks the roof is not a load-bearing accessory platform unless the manufacturer says it is. A bed rack loads the bed rails, which carry load but were not necessarily designed to resist a cantilevered mass vibrating at highway speed. Bolting to plastic trim is not mounting. A 40-inch straight bar, the format most of these discussions assume, is a housing SAEC builds as the Jungle Series 40 inch; what makes it a roof bar is the bracket and the aim, not the housing.

Roof-mounted light bars: height, glare and the legal question

The 2023 Desert Boss included a roof-mounted light bar, which shows that a factory package on this truck has included a roof bar before. That is a fact about the 2023 package, not a statement about the 2027 one, whose contents stop at the phrase “a distinctive lighting package”, and not a statement about legality.

Three questions get collapsed into one here. The first is whether the bar impairs a required lamp: under 49 CFR 571.108 S6.2.1, no additional lamp or other equipment may be installed that impairs the effectiveness of required lighting equipment, and a bar mounted in front of a high-mounted stop lamp is the kind of problem that provision addresses. The second is whether the required lamps still meet photometry and visibility with the new hardware in place, which S6.1.3.1 and S6.2.2 address. The third is whether the auxiliary lamp may be used on a public road, and the standard does not answer that at all: a forward-facing auxiliary lamp that is not a required function, and is not a replacement for one, sits outside the standard, and state law governs its use.

What FMVSS No. 108 actually says about your auxiliary lamps

The federal standard is often cited as though it approved or banned auxiliary lighting. Read closely, 49 CFR 571.108 does neither: it sets requirements for the lamps it covers and forbids modifications that degrade them.

Provision	Text in substance	What it means for an owner adding lamps
S1 and S3	The standard specifies requirements for original and replacement lamps, reflective devices and associated equipment, and applies to the listed vehicle types	The standard’s subject is the vehicle’s lighting equipment, including replacement equipment for like functions
S3.3	Applies to lamps, reflective devices and associated equipment for replacement of like equipment	A replacement lamp is within scope when it replaces a like function
S6.2.1	No additional lamp, reflective device or other motor vehicle equipment is permitted that impairs the effectiveness of lighting equipment required by the standard	The one clear prohibition on additions: do not degrade what is required
S6.1.3.1	Required lamps must be securely mounted on a rigid non-glazing part, within the Table I limits, meeting photometry and visibility with obstructions considered	A bracket that moves a required lamp, or shades it, is a compliance question
S6.2.2	If a required lamp is obstructed by equipment, an additional compliant lamp of the same type is required	Winches, bars and plows can trigger this
S6.1.3.6	An auxiliary lamp must be at least twice the distance from any required identification lamp as the distance between two adjacent required identification lamps	Rarely relevant on a pickup, relevant on a chassis-cab or a truck with identification lamps
S6.7.1.1 and S6.7.1.2	Replacement lamps must meet the requirements for that lamp type, include all functions of the lamp replaced, and must not take the vehicle out of compliance	This is the provision that governs replacement headlamps and lamp assemblies, not add-on work lights
S6.5.1.2	Lamps other than headlamps may be marked DOT, and the mark certifies conformity	A DOT mark on an auxiliary lamp is a manufacturer’s claim about that lamp, not an approval of your installation

The provision to remember is S6.2.1, the only place where an addition is directly addressed as a prohibition; everything else in the table concerns lamps that replace a like function or keeping required lamps effective. What the standard cannot do is tell you that a 40-inch bar on your roof is legal on a highway, because it has no category for it. That is why the question becomes a state question.

The state layer that the federal standard leaves open

Because FMVSS 108 does not authorise auxiliary lamps, the rules that decide when you may switch one on are state vehicle codes. Some states regulate by mounting height, some by whether the vehicle is on a highway, some by whether the lamp is covered when not in use, some by colour. The detail differs enough that a setup legal in one state can be illegal a few hundred miles away.

That makes the preparation procedural. Find the rule for the state you actually drive in and check it for the lamp type you are considering, not for the general category. Decide which lamps are for the road and which are for closed courses and private land, and wire them so the distinction is physical: separate switch, separate relay, and ideally an indicator that shows which circuit is live. A circuit that makes it easy to leave a high-output bar on is a circuit that will eventually be left on in traffic.

Aiming a lamp on a lifted ZR2 or AT4X

Aim is a geometric relationship between the lamp, the ground and the horizon, so anything that changes the truck’s attitude changes the aim. A lift, a levelling kit, a heavy winch, a loaded bed or a trailer on the hitch all move the aim plane, which is why a lamp aimed on an empty truck can glare once a load goes in.

The method is the one SAEC’s aiming and glare guide sets out: prepare the vehicle in the condition it will be driven in, park on level ground a measured distance from a wall, mark the lamp centre height, and adjust one lamp at a time so the pattern sits where the lamp’s instructions specify. Then confirm on a closed area at night, because a wall shows the pattern but not the glare.

Two mistakes are common on lifted trucks: aiming to the wall with the truck empty and then loading it, and using the roof bar as a driving light because it reaches further, which puts the beam above the windscreen line of every oncoming car.

Heat, ingress protection and the environment the Desert Boss is built for

Desert running is a thermal problem before it is a lighting problem, and the Desert Boss name is a reminder that this truck is being sold into an environment of high ambient temperature, fine dust and sustained vibration.

For a lamp, three stresses act at once in that environment. Ambient temperature reduces the temperature difference between the LED junction and the surrounding air, so the same lamp runs hotter at 45 degrees Celsius ambient than at 20. Dust deposits on a housing act as insulation and, on a lens, scatter light. Vibration loads every bracket and every connector, and the failure it produces is usually a fatigue crack or a chafed wire rather than a clean break.

Rating	What the second digit addresses	What it does not tell you
IPX8	Continuous immersion in water, under conditions agreed between the manufacturer and the tester	How deep, for how long, or whether the lamp survives pressure washing
IPX9K	High-pressure, high-temperature water jets	Whether the lamp survives immersion, mud packing or steam cleaning at close range
IP6X	Dust-tight, meaning no dust ingress under the test conditions	Whether dust that settles on the outside will bake onto the housing and insulate it
IP68 and IP69K together	Both immersion and jet protection claimed	Nothing about vibration, thermal cycling or connector sealing, which are separate failure paths

The practical reading is that an IP rating describes enclosure behaviour under defined water and dust tests and says nothing about the two mechanisms that actually kill auxiliary lamps on a truck: heat and vibration. SAEC’s guide to IP68 and IP69K explains what each test covers, and the article on thermal management explains the heat path from junction to air. The consequence for a Desert Boss owner is specific: a lamp on a front bumper bracket sees more vibration than one on a bed rack, and a lamp where air cannot flow past the housing will run hotter than its bench test predicts whatever its IP rating says.

Trailer lighting and the 7,700-pound question

A truck with a 7,700 lb tow rating will spend part of its life with a trailer behind it, and trailer lighting is a separate electrical system rather than an extension of the truck’s.

Trailers are within the scope of 49 CFR 571.108, which applies to passenger cars, multipurpose passenger vehicles, trucks, buses, trailers and motorcycles. The standard also sets a conspicuity rule for larger trailers: each trailer of 2032 mm or more in overall width with a GVWR over 10,000 lb must be equipped with retroreflective sheeting, reflex reflectors, or a combination of the two. A trailer light enough to sit behind a 7,700 lb rating may be under that threshold, which is why the rule is worth knowing rather than assuming.

Three points follow for anyone lighting a towing setup. The truck’s trailer connector type and the current available on each trailer circuit are not published in the sources used here, so the owner’s manual is the document to check. A trailer work light is an accessory on a circuit that already carries stop, turn and tail functions, so the same discipline applies: separate feed, separate fuse, separate relay, and a ground that returns to the trailer frame rather than through the hitch ball. And a lamp on a trailer sees a different vibration environment, because the trailer’s suspension is not the truck’s.

Bed lighting, cargo lamps and work-truck use

An auxiliary lamp on a truck bed is not a generic work light in the eyes of the standard. It has a name.

The definitions section of 49 CFR 571.108 defines a cargo lamp as a lamp mounted on a multipurpose passenger vehicle, truck or bus for the purpose of providing illumination to load or unload cargo. Two combination rules sit close to that definition: no high-mounted stop lamp may be combined with any other lamp or reflective device other than a cargo lamp, and no high-mounted stop lamp may be optically combined with a cargo lamp.

For an owner adding bed lighting, the second rule has teeth. A lamp that shares a lens or optical assembly with the centre high-mounted stop lamp is a combination the standard addresses directly; a lamp mounted separately on the bed rail or the rear of the cab, not sharing optics with the stop lamp, is a different situation. The distinction is optical combination, not proximity, so the question is whether light from the two functions passes through the same lens or reflector.

Work-truck buyers should also note what the powertrain coverage does not say. Business Fleet reports that the 2027 full-size trucks will complete more than 1.5 million miles of validation before reaching dealers, but that validates the powertrain, not an accessory circuit, and the trucks in this article are the mid-size ones. A fleet adding work lighting should treat the accessory circuit as its own design task; the LED work lights category is organised around that use.

Where the mid-size segment stands now

AutoGuide places the 350 hp and 455 lb-ft figures against the segment’s benchmarks, which is worth reproducing because it explains why this update matters competitively.

Truck	Output quoted in the source	Note
2027 Chevrolet Colorado and GMC Canyon, L4B TurboMax	350 hp, 455 lb-ft	The subject of this article
Toyota Tacoma, i-FORCE MAX hybrid	326 hp	AutoGuide places the GM trucks above this figure
Ford Ranger Raptor, twin-turbo V6	405 hp	AutoGuide places the GM trucks just under this figure

Two caveats belong with that table. Horsepower and torque are not a performance comparison between vehicles, because weight, gearing, tire choice and transmission calibration all intervene. And the comparison is AutoGuide’s framing, which sets a standard mid-size powertrain against a hybrid and against a performance variant: three different kinds of product.

What the numbers establish is narrower than it looks. The standard mid-size GM truck is no longer the least powerful option in that comparison, and whether that changes how it drives, tows or returns fuel economy needs a test drive and EPA figures that have not been published for the 2027 mid-size trucks. For the full-size side of the same news cycle, SAEC’s coverage of the 2027 Ford F-150 and the 2027 Chevrolet Silverado 1500 sets out what changed there.

Ordering a 2027 Colorado or Canyon: a verification checklist

Because so much of this story rests on order-guide reporting rather than a press release, the ordering process is where a buyer of the 2027 Chevrolet Colorado or Canyon can convert reported facts into confirmed ones. Each row below is a question with a document that answers it.

Item to verify	Where the answer lives	Why it matters
That the truck is a 2027 model year with the L4B engine	The order guide and the window sticker, not the sales conversation	The whole powertrain change rests on the engine code, and the model year is what the source states
The tow rating for the exact configuration ordered	The vehicle-specific rating, not the headline 7,700 lb figure	The headline figure applies to standard trucks; ZR2 and AT4X are 6,000 lb and Bison and AEV are 5,500 lb
The build date and the plant	The order acknowledgement	AutoGuide reports production starting in fall 2026 at Wentzville Assembly
Whether the Desert Boss package is available on the trim ordered	Written confirmation from the dealer	The package is reported as ZR2-only and as unavailable with the Bison and Midnight packages
What the Desert Boss lighting package actually contains	A written parts list, in advance	No output, beam, count or switch detail has been published
Whether DSSV dampers are included or extra	The option list and the price	DSSV is a $2,583 option on the ZR2 and standard on the Bison per CarScoops
The accessory warranty terms for dealer-installed parts	The accessory warranty document	Accessory coverage runs separately from the vehicle’s build warranty
Whether the vehicle has been rated by IIHS	The IIHS rating page for the model year	The current Colorado crew cab page covers 2023-2026 models, with a Marginal rating in the updated moderate overlap front test

Safety ratings lag model years, which is the point of the last row. The current IIHS page for the Colorado crew cab pickup assigns its ratings to 2023-2026 models and records a Marginal overall result in the updated moderate overlap front test, a Poor result for the standard vehicle-to-vehicle front crash prevention system and an Acceptable result for pedestrian front crash prevention. A 2027 rating is a separate publication that had not appeared at the time of writing.

Frequently asked questions

Is the 2027 Colorado’s engine the same one used in the Silverado?

It is the same engine family. GM’s specification table for the 2027 Silverado 1500 rates the enhanced 2.7L TurboMax at 350 hp at 5,200 rpm and 455 lb-ft at 3,000 rpm, and AutoGuide reports that the same L4B engine is used in the updated full-size trucks and in the mid-size Colorado and Canyon. What differs is the transmission: the full-size trucks use a ten-speed automatic, while AutoGuide reports that the mid-size trucks retain an updated eight-speed.

Does the 2027 Colorado still use an eight-speed automatic?

Yes, according to AutoGuide’s report from order-guide details, which describes the mid-size trucks as retaining an updated version of their existing eight-speed automatic while the full-size trucks move to a ten-speed. GM has not published a mid-size specification sheet confirming the calibration in the documents used for this article.

Is the Desert Boss package factory-installed?

No, according to the report. CarScoops, citing GM Authority, states that the 2027 Desert Boss Special Edition will be sold exclusively as a dealer-installed option, in contrast with the 2023 version, which was a factory-prepped special edition.

How much does the 2027 Desert Boss package cost?

The price has not been announced. For scale, CarScoops reports that the 2023 Desert Boss added $9,295 to the sticker of a regular Colorado, and that there is no word yet on what the 2027 package will cost. A 2023 figure is not a forecast for 2027.

Does the Desert Boss lighting package make its lamps legal on the road?

Not automatically, and the question conflates two things. FMVSS 108 does not authorise auxiliary lamps; it requires the lamps it covers to meet its requirements and prohibits additions that impair required lighting equipment. Whether an auxiliary lamp may be used on a public road is determined by state law, and a dealer-installed lamp is in the same position as any other auxiliary lamp.

Can I add a light bar without affecting the warranty?

The sources used here do not establish GM’s warranty position on accessory lighting, so any answer would be a guess. The defensible approach is to get the dealer’s position in writing before installation, to use a separately fused and relay-switched feed so the factory circuits are untouched, and to keep the installation documented. An installation that taps a factory lamp circuit is a different warranty conversation from one that does not.

How much auxiliary lighting can the electrical system support?

The sources used here do not publish an alternator rating or a spare accessory current budget for the 2027 Colorado or Canyon, so no figure can be given without inventing one. The workable method is to measure the current your chosen lamps actually draw, add margin, size the fuse and wire for that current, and confirm the alternator’s available headroom from the vehicle’s documentation before adding a large continuous load.

What is the 2027 Colorado’s towing capacity?

AutoGuide reports three figures, unchanged from before: 7,700 lb for standard trucks, 6,000 lb for the ZR2 and Canyon AT4X, and 5,500 lb for the ZR2 Bison and Canyon AT4X AEV Edition. The rating depends on configuration, so the vehicle-specific figure is the one that governs.

Editorial note

This article was researched, written and edited by the SAEC Lighting Engineering Team, Foshan. It keeps three tiers of information separate throughout: what General Motors has published in its own documents, what dealer order guides show as reported by trade media, and what has been reported second-hand and not confirmed by the manufacturer. Where a figure could not be verified, the article says so instead of estimating it, and where two sources disagree, both figures are given with their origins. Nothing in this article is legal advice; road-use rules for auxiliary lighting vary by state and by vehicle configuration, and they should be checked against the specific vehicle before installation.

Last updated: 2026-10-18

Sources

• AutoGuide, “2027 Chevrolet Colorado and GMC Canyon Gain Upgraded Engine,” 22 September 2026 — https://www.autoguide.com/auto/manufacturers/chevrolet/2027-chevrolet-colorado-and-gmc-canyon-gain-upgraded-engine-44639020
• CarScoops, “Chevy Is Bringing Back The Colorado Desert Boss,” 14 October 2026 — https://www.carscoops.com/2286709/chevrolet-colorado-desert-boss-returns/
• General Motors of Canada, “Chevrolet introduces the Next-Generation 2027 Silverado, available as our most powerful Silverado 1500 ever,” 16 June 2026, with pricing and specifications added 18 September 2026 — https://www.gm.ca/en/home/company/canada/oshawa.detail.html/Pages/news/ca/en/2026/jun/0616_2027-silverado-1500-most-powerful-ever.html
• Business Fleet, “2027 Silverado and Sierra Give Small Fleets Four Ways to Spec a Work Truck,” 17 September 2026 — https://www.businessfleet.com/news/2027-silverado-and-sierra-give-small-fleets-four-ways-to-spec-a-work-truck
• eCFR, 49 CFR 571.108, Federal Motor Vehicle Safety Standard No. 108: Lamps, reflective devices, and associated equipment — https://www.ecfr.gov/current/title-49/subtitle-B/chapter-V/part-571/subpart-B/section-571.108
• Insurance Institute for Highway Safety, “2026 Chevrolet Colorado crew cab pickup” ratings page — https://www.iihs.org/ratings/vehicle/chevrolet/colorado-crew-cab-pickup/2026
• SAEC, “2027 Chevrolet Silverado 1500: Engines, Towing, Trims and Price” — https://saec-lights.com/off-road-truck-industry/pickup-truck-news/2027-chevrolet-silverado-1500-engines-towing-trims/
• SAEC, “2027 Ford F-150: New 3.0L EcoBoost, Entry Tremor and Raptor, BlueCruise Towing and the Carhartt Edition” — https://saec-lights.com/off-road-truck-industry/pickup-truck-news/2027-ford-f-150-new-base-engine-carhartt-tremor-raptor/
• SAEC, “LED Light Bar Wiring Kit Buying Guide: Relays, Fuses and Switches” — https://saec-lights.com/buying-guides/led-light-bar-wiring-kit-buying-guide/
• SAEC, “Auxiliary Light Aiming and Glare: A Practical Safety Guide” — https://saec-lights.com/standards-safety/auxiliary-light-aiming-glare-safety-guide/
• SAEC, “DOT vs E-Mark: How to Read a Vehicle Light’s Approval Marking” — https://saec-lights.com/standards-safety/dot-vs-e-mark-vehicle-light-approval-markings/
• SAEC, “Why Heat Matters: LED Light Bar Thermal Management Explained” — https://saec-lights.com/lighting-basics/led-light-bar-thermal-management-explained/