2021 GMC SIERRA 2500 Exterior Lighting Problems

My right headlamp/ turn signal assembly began flashing at random intervals. The high beam would come on and off randomly. The entire assembly would randomly flash along with the turn signal. The headlamp would go on and off randomly. This included switching between setting. High beam, low beam, daytime running light, and completely off with no warning. This causes blinding conditions for oncoming drivers, loss of visibility for driver, and loss of visibility during inclement weather due to high beam coming on and off, then entire unit turning off. As of right now, the vehicle is undrivable due to incorrect lighting, and flashing lights.

Known issue and has been attributed to a manufacturing defct, but no recall- Leaking headlight caused damage to headlight- now turn signal and headlight do not work. Entire assembly needs to be replaced, GM / Extended Warranty Company will not cover, this safety part. Head light and turn signal were working on the way to the dealer, 1 month later when we picked it up - Right turn signal malfuction reading appeared on dash, headlight blinking and will not work. Picked up on Friday 1/30/25, and made an appointment for the following Wednesday to take it back in. Was told by dealer today that the replacement will not be covered and will cost $2100.00 to replace. This is a safety part and the truck can not be driven legally or safely without both headlights working.

Headlight vent failed. Hid control board filled up with moisture. Headlight is flashing like emergency vehicle if it turns on at all.

The front left headlamp assembly low beam light unexpectedly began to flicker repetitively until the vehicle was turned off. In addition, the left front turn signal was failed, but an indication of the failed turn signal was not always present. The headlamp assembly was taken in for replacement at a local GMC dealership promptly due to safety concerns of operating the vehicle on public roadways with this condition. The safety of others was at risk due to the strobing effect of the flickering lights and not being able to drive the vehicle during conditions where headlights are necessary. The flickering/strobing condition of the headlamp was highly distractive and puts other drivers are risk. In addition, due to the natural height of the vehicle the cast of the beam is closer to the rear view mirror height of the majority of vehicles. The problem was confirmed by a local GMC dealership...

Headlights and turn signals failed. Flickering of various lights (Daytime running lamp, low beam, high beam, turn signals) followed by total failure. 3700 dollar repair at dealer to replace both headlamp assemblies. Barely over miles of warranty, but still in the 3 year warranty time period. Not having forward lighting is of course a major safety issue. Vehicle should be recalled. Many others are having the issue.

On 11/21/24 noticed passenger headlight day light running light flickering. On 11/22/24 right turn indicator intermittent fast blink, dash message stated turn indicator failure. Once home, inspected passenger headlight assembly. Found DRL, turn signal, and low and high beam head lights were inoperative. On 11/25/24 went to GMC dealer/service. Staff seemed aware of issues and stated they are common, that they carry the $1,400 sealed assebly in stock. Vehicle is 4 months over warranty, but only has 29,000 miles. There is no visible damage to the assembly, but there is visible condensation inside the lens. GM has a published service bulletin, 01-08-42-001P, that specifically addresses this issue for my vehicle. The earliest date the issue could be diagnosed/service date is 12/10/24. A complete failure of this non-servicable headlight assembly is an absolute safety issue. Decreased daytime visability with the loss of one of two Daytime Running Lights, the lose of...

3 year old truck. The left headlight enclosure gained water and caused the whole headlight system to have issues. Water caused the Headlights to Flash high beams (both), turn off and blinkers not to work. This defect the whole side that is effective. This can cause other drivers or the owner to have an accident. 6 months later, Now the right side headlight is doing the same. I’m out of warranty with only 40k miles. The seal is not strong enough to keep water out the enclosure. This can also cause the whole light system to shut down while driving. Very dangerous especially at night.

The driver side headlamp stopped working, Condensate buildup may be a contributing factor. No accident and vehicle is meticulously maintained. No reason for lamp seals to be damaged or wear. Barely three years old and requires a replacement at $1400 for the part and another $1000 in labor. Outside of 36000 mile warranty.

Passenger headlight light fills up with moisture resulting in the HID module filling up with water and shorting out. The high beam starts flashing when you try to use your turn signal and eventually the headlights completely stop working. Is a known problem, but GM won’t do anything to help if you’re outside of the 3year/36,000 mile warranty. Currently unable to get a new headlight because of the on going strike.