Fog Lights Circuit Description Luxury

Fog lamp operation is possible with the headlamp and panel dimmer switch in the PARK position or in the HEAD position. However, if the headlamp and panel dimmer switch is in the HEAD position, the fog lamps are only operational if the headlamp dimmer switch is in the LOW position.

With the headlamp and panel dimmer switch in the PARK position or the HEAD position (if the switch is in the HEAD position, the headlamp dimmer switch must be in the LOW position), voltage is available through the closed contacts of the park lamp switch to the fog lamp switch. With the fog lamp switch in the ON position, voltage is available through the closed contacts of the fog lamp switch to the coil (power side) of the fog lamp relay. Voltage is available to the contact side of the relay through the DRL-FOG fuse 15.

Ground is available from the daytime running lamps (DRL) module to the coil (ground side) of the fog lamp relay, provided that the headlamp dimmer switch is in the LOW position, if the headlamp and panel dimmer switch is in the ON position.

With both power and ground available to the coil of the fog lamp relay, the relay energizes. Then, voltage is available through the closed contacts of the relay to the fog lamp ON indicator, the left fog lamp, and the right fog lamp.

The indicator lamp and the fog lamps light. If the selection of the headlamp dimmer switch changes to the HIGH position when the headlamp and panel dimmer switch is in the HEAD position and the fog lamp switch is in the ON position, then the DRL module receives a high beam headlamp operation signal. Then the DRL module disables the fog lamp relay. This extinguishes the fog lamps.

Fog Lights Circuit Description Z71 Tahoe/Limited

This system incorporates a fog lamp switch, fog lamp relay and two fog lamps. This system will operate whenever the ignition switch is in the ON position and does not have to have the park lamps on. However, if the headlamps are on and in the high beam position, the ground to the fog lamp relay coil is interrupted and the fog lamps turn off.

Voltage is supplied to the fog lamp switch through CKT 241 (BRN) from the 4WD fuse 24 in the IP fuse block. When the fog lamp switch is in the ON position, voltage is supplied to the fog lamp relay coil through CKT 317 (YEL). Since the relay coil is connected to the high beam headlamp through CKT 11 (LT GRN) to ground the relay energizes. Since the input side of the relay is connected to the CTSY fuse 3 in the IP fuse block through CKT 40 (ORN), voltage is supplied to CKT 34 (PPL) to the fog lamps and to the ON indicator in the fog lamp switch. Ground for the fog lamps is supplied from G113 and the ON indicator from G200 through CKT 150 (BLK) and the fog lamps and the indicator illuminate. Backlighting for the fog lamp switch is provided through CKT 8 (GRY) to the headlamp and panel dimmer switch and grounds to G200 through CKT 150 (BLK).