GM Service Manual Online
For 1990-2009 cars only

Front

The fuse H5-H6 supplies voltage through circuit 9 to the front fog lamp switch. When the front fog lamp switch is turned to the ON position voltage is supplied through circuit 317 to the coil side of relay 16. The ground for the relay is supplied through circuit 451. This energizes the relay closing the contacts on the switch, allowing voltage to be supplied through the closed contacts of the relay to the front fog lamps. The front fog lamps are grounded through circuit 451

Rear

The Fuse F3-F4 supplies voltage through circuit 1840 to the coil side and switch side of the rear fog lamp relay. When the rear fog lamp switch is turned to the ON position, ground is applied from circuit 1350 through the rear fog lamp switch to circuit 1977. The body control module receives the ground from circuit 1977 and applies a ground to the coil side of the rear fog lamp relay through circuit 1317. This energizes the relay, causing the switch contact to close, and applying voltage to circuit 122 to the rear fog lamps. The rear fog lamps are grounded through G402.