The headlamps, Daytime Running Lamps (DRL), parking lamps and/or turn signals may be intermittently inoperative on some 2024-2026 Silverado 2500HD/3500HD and Sierra 2500HD/3500HD trucks. (Fig. 1) Lighting operation may recover after the ignition is cycled.
Fig. 1
The intermittent operation of the front lighting may be due to an internal failure of the Multi-purpose LED Driver (MLD), which controls the lighting functions of the lamp assembly. (Fig. 2: A. MLD on the Chevrolet assembly. B. MLD on the GMC assembly). If the MLD has failed, it must be replaced.
Fig. 2
TIP: Before replacing the MLD, refer to Bulletin #25-NA-337 and verify the Julian date and part number of the headlamp assembly. A soldering issue on some lamps may cause the lighting functions to become inoperative on some 2025 Sierra 2500HD/3500HD models. Affected headlamps should be replaced. (Fig. 3)
To replace the MLD, refer to Front Headlamp Replacement in the appropriate Service Information.
Fig. 3
Once the headlamp has been removed, the MLD can be removed from the assembly. Install the new MLD in the assembly and confirm the seal is positioned correctly against the housing. The screws securing the MLD should be tightened by hand, taking care not to strip the holes in the housing.
Before reinstalling the headlamp assembly, check for proper operation. If the lighting does not work properly, replace the headlamp assembly.
Refer to Bulletin #26-NA-002 for more information, including part numbers.
– Thanks to Kevin Minor
