GM Service Manual Online
For 1990-2009 cars only

The body control module (BCM) generates a fasten belts warning for 4-8 seconds and illuminates the fasten seat belt indicator when the BCM senses both of the following conditions:

    • The ignition switch is in the RUN, BULB TEST or START position.
    • The driver seat belt is unbuckled.

When the ignition switch is in the RUN, BULB TEST or START position, voltage is applied to the BCM ignition positive voltage input. With the driver seat belt unbuckled, ground is applied to the BCM seat belt switch signal input. The BCM applies voltage to the instrument cluster to illuminate the fasten seat belt indicator. The indicator remains ON for approximately 70 seconds. The indicator turns off if the seat belt is buckled.

If the driver seat belt is buckled before the ignition switch is turned to the RUN, BULB TEST or START positions the following will occur:

    • The fasten seat belt warning will not sound.
    • The fasten seat belt indicator will not illuminate.