Without Fog Lights

With the Ignition Switch in RUN, the Light Switch not in HEAD and the Park Brake released, the Daytime Running Lights (DRL) Module grounds the coil of the DRL Relay. In the coupe and sedan, Ignition voltage is supplied to the DRL Module and DRL Relay coil from the FOG Fuse (with UB3) or HTR-A/C Fuse (with UH7). In convertible vehicles, the DRL Ignition Relay supplies voltage to the DRL Relay coil and contacts and to the DRL Module. The DRL Relay is energized, and battery voltage is applied to the ground side of the LH HI Beam Headlight, allowing voltage to also be applied to the RH HI Beam Headlight. This series circuit arrangement causes the voltage across each HI Beam Headlight to be exactly half the battery voltage, reducing Headlight brilliance for the DRL mode operation.

When the Light Switch is in HEAD and the Headlight Dimmer Switch is in LO, battery voltage is applied to the Light Switch Input of the DRL Module via CKT 10. The module de-energizes the DRL Relay, applying ground to the LH HI Beam Headlight. Battery voltage is applied to the LO Beam Headlight filaments via CKT 12.

When the Light Switch is in HEAD and the Headlight Dimmer Switch is in HI, battery voltage is applied to the HI Beam Input of the DRL Module via CKT 11. The Module de-energizes the DRL Relay, removing voltage from CKT 593 and disengaging DRL mode operation. With the relay de-energized, the ground path through the DRL Relay to the LH HI Beam Headlight is restored. Battery voltage is applied to the HI Beam Headlights via CKT 11.

The Daytime Running Lights (DRL) Module has an input from the BRAKE Indicator control circuit. When the Park Brake is set, ground is applied to the DRL Module Park Brake Applied Input. The DRL Module then removes ground from the DRL Relay, and the relay is de-energized, removing battery voltage from the HI Beam Headlights. Because the Park Brake Switch shares CKT 33 with the Electronic Brake Control Module (EBCM) and the Brake Fluid Level Switch, any condition that causes the BRAKE Indicator to come on will also inhibit the HI Beam Headlights from operating in Daytime Running Lights mode.