Posts Tagged: GM daytime running lights

GM daytime running lights don’t work

Diagnose and fix GM daytime running lights GM uses a few different daytime running light schematics, but most use a series wiring method that divides battery voltage in half through series wiring. Here’s how that GM daytime running lights system works. How GM daytime running lights work Thirty seconds after you start your vehicle with the headlights off, the body control module (BCM) checks the voltage on the ambient light sensor. For the DRL system to work, the IGN must be in the RUN position, the parking brake must not … Read More