Liberty Sport 4WD L4-2.4L VIN 1 (2002)
Hi-Beam Indicator Lamp: Description and Operation
A high beam indicator lamp is standard equipment on all instrument clusters. The high beam indicator is located near the upper edge of the instrument
cluster overlay between the tachometer and the speedometer. 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 the it is not illuminated. A blue Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay causes
the icon 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. The high beam indicator is serviced as a unit with the instrument cluster.
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 electronic circuit board based upon the 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.
-
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 to determine the proper outputs to the headlamp low beam and high beam
relays. The BCM then sends the proper high beam indicator 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 INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For
proper diagnosis of the headlamp system, the BCM, the PCI data bus, or the electronic message inputs to the instrument cluster that control the high
beam indicator, a DRBIII scan tool is required. Refer to the appropriate diagnostic information.
