Front Fog Lamp Indicator

The front fog lamp indicator gives an indication to the vehicle operator whenever the front fog lamps are illuminated. This indicator is controlled by a transistor on the IC circuit board based upon programming and electronic messages received by the IC from the BCM over the CAN data bus.

The front fog lamp indicator LED is completely controlled by the IC logic circuit, and that logic will allow this indicator to operate whenever the IC receives a battery current input on the fused B(+) circuit. Therefore, the LED can be illuminated regardless of the ignition switch status. The LED only illuminates when it is provided a path to ground by the IC transistor. The IC will turn ON the front fog lamp indicator for the following reasons:

• Front Fog Indicator Lamp-On Message  - Each time the IC receives an electronic front fog indicator lamp-ON  message from the BCM indicating the front fog lamps are turned ON, the front fog lamp indicator will be illuminated. The indicator remains illuminated until the IC receives a lamp-OFF message from the BCM, or until the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.

The BCM continually monitors a hard wired input from the exterior lighting switch to determine the appropriate outputs to the front fog lamps. The BCM activates or deactivates the front fog lamps then sends the proper lamp-ON or lamp-OFF message to the IC to control the front fog lamp indicator.

For proper diagnosis of the front fog lamp system, the BCM, the IC, the CAN data bus or the electronic communication related to front fog lamp indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.