Liberty Sport 2WD L4-2.4L VIN 1 (2002)
Seat Belt Reminder Lamp: Description and Operation
SEATBELT INDICATOR
A seatbelt indicator is standard equipment on all instrument clusters. The seatbelt indicator is located above the fuel gauge and to the right of the
tachometer in the instrument cluster. The seatbelt indicator consists of a stencil-like cutout of the International Control and Display Symbol icon
for "Seat Belt" 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 red Light Emitting Diode (LED)
behind the cutout in the opaque layer of the overlay causes the icon to appear in red 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 seatbelt indicator is serviced as a
unit with the instrument cluster.
The seatbelt indicator gives an indication to the vehicle operator of the status of the driver side front seatbelt. 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 Airbag Control Module (ACM) over the Programmable Communications Interface (PCI) data bus. The seatbelt indicator Light Emitting
Diode (LED) is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the
instrument cluster receives a battery current input on the fused ignition switch output (run- start) circuit. Therefore, the LED will always be OFF
when the ignition switch is in any position except ON or Start. The LED only illuminates when it is provided a path to ground by the instrument
cluster transistor. The instrument cluster will turn ON the seatbelt indicator for the following reasons:
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Seatbelt Reminder Function - Each time the cluster receives a battery current input on the fused ignition switch output (run-start) circuit, the
indicator will be illuminated as a seatbelt reminder for about seven seconds, or until the ignition switch is turned to the OFF position,
whichever occurs first. This reminder function will occur regardless of the status of the electronic seat belt lamp-ON or lamp-OFF messages
received by the cluster from the ACM.
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Seat Belt Lamp-ON Message - Following the seatbelt reminder function, each time the cluster receives a seat belt lamp-ON message from the
ACM indicating the driver side front seat belt is not fastened with the ignition switch in the Start or ON positions, the indicator will be
illuminated. The seat- belt indicator remains illuminated until the cluster receives a seat belt lamp-OFF message, or until the ignition switch is
turned to the OFF position, whichever occurs first.
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Actuator Test - Each time the cluster is put through the actuator test, the seatbelt 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 ACM continually monitors the status of both front seat belt switches to determine the proper airbag system response to a frontal impact of the
vehicle. The ACM then sends the proper seatbelt indicator lamp-ON and lamp-OFF messages to the instrument cluster based upon the status of the
driver side front seat belt switch input. For further diagnosis of the seatbelt indicator or the instrument cluster circuitry that controls the indicator,
(Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). For proper diagnosis of the seatbelt switches, the ACM, the PCI data bus,
or the electronic message inputs to the instrument cluster that control the seatbelt indicator, a DRBIII scan tool is required. Refer to the appropriate
diagnostic information.
