Daytime Running Lamps (DRL)

WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.

Daytime running lamps (DRL) are standard equipment on all models. With the ignition switch in START, voltage is applied to the DRL control module through the gauge fuse. Operating through the low beams at 80 percent intensity of the normal output, a number of conditions must be met before the daytime running lamps system will work properly:

The engine is running.
The light switch is in either the OFF or the PARK lamp position.
The ambient light sensor senses a bright light condition.
When the above conditions are met, a path to ground is provided to the coil of the head relay. Voltage is applied through the closed contacts of the head relay, through the dimmer relay and the head fuses (L HLP and R HLP) to the low beam lamps in the headlamps. A path to ground is then provided through the DRL control module which reduces the intensity of the headlamps to 80 percent.

The following will prevent DRL operation:

When the generator is not running, a switch in the generator closes, providing a ground to the DRL control module, disabling the DRL operation.
When the light switch is in the head position.