One problem related to warning has been reported for the 2021 GMC Sierra 2500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2021 GMC Sierra 2500 based on all problems reported for the 2021 Sierra 2500.
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.