Front Fog Lamps

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The front fog lamp relay coil and switch terminals are supplied with battery voltage at all times. Ground is applied at all times at G200 to the front fog lamp switch inside of the turn signal/multifunction switch. When the front fog lamp switch is placed in the ON position, ground is applied through the front fog lamp switch signal circuit to the body control module (BCM). The body control module (BCM) energizes the front fog lamp relay coil by applying ground to the front fog lamp relay control circuit. When the front fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the FRONT FOG LAMP fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps. Ground for the front fog lamps is applied at all times at G101 for the left fog lamp and G102 for the right fog lamp.

The BCM will send a message GMLAN serial data to the instrument panel cluster (IPC) to enable the front fog lamp indicator. The front fog lamps will deactivate when either the flash-to-pass or the high beam headlamps are turned ON.