Subject: | DRLs Will Not Disable with Headlamp Switch |
Models: | 2003-2008 All GM Full Size Trucks and Utilities |
This PI was superseded to update model years. Please discard PIT3219B.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Some customer may state that the Daytime Running Lamps (DRL's) or the auto headlamps will not shut off when using the daytime running lamp disable switch (Which is part of the headlamp switch). Vehicles that were built in Canada and have RPO option (Z49) were built with different software that doesn't allow the DRL's or Auto headlamp to be shut off. Canada law prohibits disabling daytime running lamps (DRL's) or auto headlamps.
This is a normal operation of the vehicle and no repairs should be attempted.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.