GM Service Manual Online
For 1990-2009 cars only

Safety Belt Warning Chime

Voltage is supplied to the body control module (BCM) through the following components when the ignition switch is in the START or RUN position:

    • The GAUGES fuse 4
    • CKT 39 (PNK)

When you first turn the ignition switch to the START or RUN position, a class 2 signal from the BCM is sent to the instrument cluster logic turning ON the fasten seat belt indicator. The indicator comes ON steady for 20 seconds and then flashes for another 55 seconds if the drivers safety belt remains unbuckled, or goes out when the drivers safety belt is buckled. When is drivers safety belt is buckled, ground is no longer applied to the BCM through CKT 238 (BLK/WHT) from the seat belt switch causing the lamp and chime to go out. The chime will only sound for about the first 5 seconds of the ignition on cycle.

Key-In Warning Chime

Voltage is supplied at all times to the BCM through the following components:

    • The Underhood Fuse Block TBC fuse
    • CKT 1140 (ORN)

The chime sounds if all of the following conditions exist:

    • The key is in the ignition switch.
    • The ignition switch is in one of the following positions:
       - ACC
       - LOCK
       - OFF
    • The LH front door is open.

When the ignition key is in the ignition switch and the LH front door is open, the ignition key alarm switch closes. The LH door jamb switch also closes. When both of the switches close, the Body Control Module (BCM) senses ground through the following components:

    • CKT 126 (TAN)
    • The LH Door Jamb Switch
    • CKT 1050 (BLK)
    • SP203
    • C203 cavity F12
    • G203

The chime will sound for as long as the door is open and the key is in the ignition switch.

Lamps-On Warning Chime

Voltage is supplied through the ILLUM Fuse 12 to the BCM through CKT 44 (DK GRN) when the following conditions exist:

    • The headlamp switch is in the HEAD or PARK position.
    • The ignition switch is not in the RUN or START position.
    • The IP dimmer switch is not at the dimmest setting.

With the IP dimmer switch at the dimmest setting, the current to the BCM may be too weak to be sensed by the module. When the ignition switch is turned to the RUN or START position, voltage is supplied from the GAUGES Fuse 4 to the body control module through CKT 39 (PNK). When the ILLUM and GAUGES Fuse voltages are sensed at the same time, the alarm is not sounded. GAUGES Fuse 4 loses voltage when the ignition switch is in one of the following positions:

    • LOCK
    • OFF
    • ACC