Headlights/Daytime Running Lights (DRL)

The daytime running lamps (DRL) lights are controlled by the body control module (BCM) via the DRL relay when the headlamp and panel dimmer switch is the AUTO position.

The relay is feed by the IGNE fuse when the ignition switch is in the run and crank position, (the coil side of the relay), and the DRL fuse which is hot at all times. The DRL relay is controlled by the BCM based on the input form the ambient light sensor via CKT 592.

The relay supplies current to the lights through CKT 545 and ground through CKT 150 and ground G100.

The DRL lights are on when the vehicle ignition switch is in the run position, park brake is not set, daylight conditions exists and the transmission has been in drive before placing in park. The DRL lights are turned off when the headlamp and panel dimmer switch is turned to the park or head position or the input to the BCM from the ambient light sensor signals that daylight conditions does not exists any more.

NOTE: (For US application only, Prohibited in Canada (RPO Z49)) You may, for the current ignition on cycle, turn off the DRL and the Automatic Headlamp (AHL) feature by following the steps below:

1. The ignition is in the Run position.
2. Press the dome lamp defeat switch 4 times. After the 4th press of the switch the chime will sound informing you the procedure is complete. Turning the ignition off and then on will place the DRL and AHL back in the automatic mode. This does not apply to some early built pickups.

For a description of the RPO Code(s) shown in this article refer to the RPO Code List found at Vehicle/Application ID RPO Codes