Commander 4WD V8-4.7L VIN N (2006)
Hi-Beam Indicator Lamp: Description and Operation
HIGH BEAM INDICATOR
DESCRIPTION
A high beam indicator is standard equipment on all instrument clusters. This indicator is located near the top of the cluster overlay, between the
speedometer and the tachometer.
The high beam indicator consists of a stencil-like cutout of the International Control and Display Symbol icon for High Beam in the opaque layer of the
instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when it is not illuminated. A blue Light
Emitting Diode (LED) behind the cutout in the opaque layer of the overlay causes the indicator to appear in blue through the translucent outer layer of
the overlay when it is illuminated from behind by the LED, which is soldered onto the instrument cluster electronic circuit board.
When the exterior lighting is turned ON, the illumination intensity of the high beam indicator is dimmable, which is adjusted along with the cluster
illumination lighting using the panel lamps dimmer control sleeve on the left multifunction switch control stalk.
The high beam indicator is serviced as a unit with the instrument cluster.
OPERATION
The high beam indicator gives an indication to the vehicle operator whenever the headlamp high beams are illuminated. This indicator is controlled by a
transistor on the instrument cluster circuit board based upon the cluster programming and electronic messages received from the Front Control Module
(FCM) over the Controller Area Network (CAN) 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 Input - Each time the cluster receives a high beam headlamps-on electronic message from the FCM the high beam
indicator will be illuminated. The high beam indicator remains illuminated until the cluster receives a high beam headlamps-off message from the
FCM, or until the exterior lamp load shedding (battery saver) timed interval expires, whichever occurs first.
-
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 instrument cluster continually monitors the electronic messages from the FCM to determine the proper headlamp high beam indicator control. For
proper diagnosis of the headlamps, or the headlamp switch and multi-function switch inputs to the instrument cluster that control the high beam indicator,
a diagnostic scan tool is required.
