Grand Cherokee 2WD L6-4.0L VIN S (1997)
Malfunction Lamp / Indicator: Description and Operation
Air Bag Warning Lamp
SYSTEM OPERATION
The airbag indicator lamp gives an indication when the airbag system is faulty or inoperative. The lamp is turned on by the instrument cluster
circuitry for about seven seconds when the ignition switch is turned to the On position as a bulb test. After the bulb test, the lamp is controlled by
the instrument cluster circuitry based upon a message received from the Airbag Control Module (ACM) on the Chrysler Collision Detection
(CCD) data bus.
The ACM continually monitors the airbag system circuits and sensors to decide whether the system is in good operating condition. The ACM then
sends the proper message to the instrument cluster on the CCD data bus to turn the lamp on or off. If the ACM turns the lamp on after the bulb test,
it indicates the ACM has detected a system malfunction and/or that the airbag system has become inoperative. Each time the instrument cluster
circuitry receives a lamp-on message from the ACM, it will light the lamp for twelve seconds or the duration of the airbag system malfunction,
whichever is longer.
The airbag indicator lamp also has a lamp backup feature. Following the seat belt reminder lamp display function, if an inoperative airbag warning
lamp circuit was detected during the bulb test sequence, the instrument cluster circuitry will flash the seat belt reminder lamp on and off for about
twenty seconds. If the seat belt reminder lamp flashes longer than twenty seconds, or flashes at any time other than about twenty seconds after
the initial ignition-on sequence, it indicates an airbag system fault has been detected and that the airbag indicator lamp is inoperative.
Refer to Passive Restraint Systems for more information on the airbag system.
