Rear Fog Lamp Indicator

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

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

• Rear Fog Indicator Lamp-On Message  - Each time the IPC receives an electronic rear fog indicator lamp-ON  message from the BCM indicating the rear fog lamps are turned ON, the rear fog lamp indicator will be illuminated. The indicator remains illuminated until the IPC 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 electronic exterior lighting request  messages from the IPC to determine the appropriate outputs to the rear fog lamps. The BCM activates or deactivates the rear fog lamps then sends the proper lamp-ON or lamp-OFF message back to the IPC.