What mirrors does your rig have? There are two…
The “base” mirrors are assigned RPO code DL3 and are described as:
Mirrors, outside chrome cap, heated power-adjustable, power-folding and driver-side auto-dimming, with integrated turn signal indicators and puddle lamps (includes driver’s side spotter mirror)
The optional, up-level mirrors are assigned RPO Code DQS and are part of the Duramax Plus Package, and are described as:
Mirrors, outside heated power-adjustable vertical trailering, memory equipped, upper glass, power-folding and manual extending, chrome. Includes integrated turn signal indicators, consisting of 51 square inch flat mirror surface positioned over a 24.5 square inch convex mirror surface with a common head and lower convex spotter glass (convex glass is not heated and not power-adjustable) and addition of Auxiliary cargo lamp for backing up (helps to see trailer when backing up with a trailer) and amber auxiliary clearance lamp.