High Beam Indicator: Operation

WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.

The high beam indicator gives an indication to the vehicle operator whenever the headlamp high beams are illuminated. In certain markets where required, the high beam indicator also gives an indication when the optional light bar lamps are illuminated. This indicator is controlled by a transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Body Control Module (BCM) over the Programmable Communications Interface (PCI) data bus.

The high beam indicator Light Emitting Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will allow this indicator to operate whenever the instrument cluster 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 instrument cluster transistor. The instrument cluster will turn on the high beam indicator for the following reasons:

High Beam Headlamps-On Message - Each time the cluster receives a high beam headlamps-on message from the BCM indicating the headlamp high beams are turned On, the high beam indicator will be illuminated. The indicator remains illuminated until the cluster receives a high beam headlamps-off message from the BCM.
Light Bar Lamps-On Message - This function of the high beam indicator applies only to vehicles equipped with the optional light bar lamps and manufactured for certain markets where it is required. Each time the cluster receives a light bar lamps-on message from the BCM indicating the light bar lamps are turned On, the high beam indicator will be illuminated. The indicator remains illuminated until the cluster receives a light bar lamps-off message from the BCM.
Actuator Test - Each time the cluster is put through the actuator test, the high beam indicator will be turned on, then off again during the bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.

The BCM continually monitors the exterior lighting (multi-function) switch and the optional light bar lamp switch to determine the appropriate outputs to the headlamp low beam, headlamp high beam, and light bar lamp relays. The BCM then sends the proper high beam indicator and light bar lamp-on and lamp-off messages to the instrument cluster. For further diagnosis of the high beam indicator or the instrument cluster circuitry that controls the indicator, (Refer to ELECTRICAL/INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING) .

For proper diagnosis of the headlamp system, the light bar lamp system, the BCM, the PCI data bus, or the electronic message inputs to the instrument cluster that control the high beam indicator, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.