All (Except Envoy, Diamond Edition W/HID and ZR2)

The DRL relay is supplied battery positive voltage by the FOG LP fuse in the underhood fuse block. When the BCM requests DRL operation, the DRL relay coil and headlamp grounding relay coil are grounded by the BCM activating both relays. The energized headlamp grounding relay removes the ground utilized in normal headlamp operation to the multifunction headlamp dimmer switch. The energized DRL relay reroutes the LH high beam supply voltage circuit to ground at G102. These actions result in the LH and RH high beam headlamps to function in a series circuit at a reduced intensity.

On some vehicles, the DRL will turn OFF when the turn signal lamps are activated. This is controlled by the BCM and is a normal condition.

"For a description of the RPO Code(s) shown in this article or any of the images therein, refer to the RPO Code List found at Vehicle/Application ID". RPO Codes