Battery voltage is supplied to the FOG LAMP relay coil through CKT 317 with the headlamp and the instrument panel lamp dimmer switch in the HEAD or the PARK position, and the fog lamp switch in the ON position. The coil is grounded through the high beam filaments through CKT 11. The relay energizes and applies voltage to the fog lamps through CKT 34. Since the coil of the FOG LAMP relay is grounded through the high beam filaments, the relay will de-energize any time the high beams are ON because equal voltage is applied to both sides of the relay coil. The daytime running lamp (DRL) control module applies voltage through CKT 9 to the fog lamp switch and to the exterior lights when the headlamp and the instrument panel lamp dimmer switch is in the OFF position.