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For the 2015 model year, the GMC Sierra 2500 experienced a serious redesign. The automaker hoped to match the interior and exterior styling with the light-duty Sierra 1500 launched the year prior.

GM added many new standard features and fine-tuned the body and chassis. Paired with a six-speed automatic transmission, this heavy-duty truck had a 6.0-liter V8 engine that developed 360 hp and 380 lb-ft.

While it was neither the quickest nor the most capable towing truck in its segment, the Sierra was tough enough to get the job done. However, owners of the 2015 Sierra would probably tell you otherwise. The truck had a serious safety flaw, as details.

The GMC Sierra 2500’s big problem

The Sierra’s problem was its projector headlights, which were a standard feature in 2015. The low-beam headlights gave off such sparse light that some owners were forced to regularly use high beams. They also felt that the dim headlights made their trucks less visible to other drivers.

Sixteen Sierra owners submitted grievances to The website gave this issue a “really awful” rating of 9.2 and was the overall worst problem category for the truck.

The worst part of the issue occurred when drivers needed to turn into poorly-lit areas since the headlights failed to project lateral illumination. This means, for example, that a driver may not see a pedestrian as he or she turns into a dark driveway. Sierra owners were concerned that this severe defect would ultimately cause injury or death. The National Highway Traffic Safety Administration validated this concern, posting 56 complaints about the defect.

The headlights’ angle seemed to be a key part of the problem. Owners noticed that the lights failed to overlap when illuminating the road, which created a stripe of darkness between the headlight beams. One driver speculated that only about half of the headlights’ usable light was available because it was blocked by a shield on the headlights. Another driver commented that the headlights were about as effective as a flashlight.

A frustrating aspect of the problem was that it emerged soon after owners purchased the Sierra. They were disappointed to have spent more than $55,000 on a truck with defective headlights. To add insult to injury, one owner was told by a GMC dealership that drivers weren’t accustomed to the light that projector headlights produce. Owners sometimes had to resort to finding their own solutions when the dealerships didn’t.

The Sierra 2500’s unsatisfactory solution

A few owners were able to troubleshoot the problem and upgrade the headlights’ xenon HID bulbs. They either replaced the bulbs themselves or had the dealerships do the work. Even with the upgrade, one owner noted there was still a line of darkness between the headlights. After suspecting a defective assembly in the Sierra’s headlights, one driver even did his own aiming test in a totally dark airplane hangar.

More owners, however, could not find answers. Some of them moved on to trucks with reliable headlights. But nine of the 16 who reported the problem found no resolution for the issue.

The irony is that projector headlights are supposed to provide increased brightness because their lenses function like a magnifying glass. They are less likely to blind other drivers because they are directed down toward the road. They should also give off a more even light than reflector headlights.

Clearly, the 2015 GMC Sierra’s headlights not only failed to live up to these advantages but they also failed any expectation of working like headlights of any kind. 

Sierra 2500 model years that don’t have this problem

When shopping for a used GMC Sierra 2500, you’ll want to avoid the 2015 model’s headlight issue altogether. While the 2016 model year still seems a bit problematic, according to, the 2014 model year has only one complaint about the headlights.

From this year back to 2009, there are no headlight complaints. The 2018 Sierra also seems to have fewer headlight problems. Being aware of the 2015 model’s problem is the first step toward buying a pre-owned Sierra that is safe.