GM Service Manual Online
For 1990-2009 cars only

Module Power

Battery positive voltage is applied on CKT 540 (ORN) and CKT 640 (ORN) to the body control module (MALL) connector C1 terminal H and terminal G respectively. With the ignition switch in the RUN or the START position, the ignition positive voltage is applied on CKT 39 (PNK) to the MALL module connector C2 terminal C13.

Lamps On Chime

The fast-pulsed lamps on chime sounds when the following conditions are present:

    • The left front door is open.
    • The MALL does not detect voltage at the lamps off input CKT 1785 (LT BLU).
    • There is no voltage at ignition CKT 39 (PNK).

Key In Ignition Chime

The key in ignition chime sounds when the following conditions are present:

    • An ignition key is in the ignition switch.
    • The left front door is open.

When a key is in the ignition switch (the key-in-ignition switch is closed), a ground condition exists on one of the following circuits:

    • CKT 80 (LT GRN) (without keyless entry)
    • CKT 653 (DK BLU/WHT) (with keyless entry)

When the left side front door is open (the left side front door jamb switch is closed), a ground condition exists on CKT 126 (TAN).

The medium-pulsed key in ignition chime sounds when the following conditions are present:

    • The MALL detects a ground condition at both circuits.
    • There is no ignition positive voltage on CKT 39 (PNK).

Fasten Seat Belts Chime and FASTEN BELTS Indicator

The fasten seat belts chime sounds when the following conditions are present:

    • The ignition switch is in the RUN or START position.
    • The left front seat belt is unbuckled.

When the ignition switch is in the RUN or START position, ignition positive voltage is applied on CKT 39 (PNK) to the MALL. When the left front seat belt is unbuckled (the seat belt switch is closed), a ground condition exists on CKT 238 (BLK/WHT). The MALL applies voltage on CKT 234 (YEL) for 70 seconds when the following conditions are present:

    • The MALL detects a ground condition on CKT 238 (BLK/WHT).
    • There is ignition positive voltage on CKT 39 (PNK).

This application of voltage causes the following actions to occur:

    • The FASTEN BELTS indicator illuminates.
    • The fasten seat belts chime sounds for 4-8 seconds.

Turn Signal On Chime

When a turn signal is operated, the MALL begins to monitor the vehicle distance. If the turn signal is still flashing after the vehicle has traveled 1.2 km (3/4 mi), the turn signal on chime sounds 4 times.

Park Brake Chime

Refer to Brake Warning Circuit Operation, Brake Warning System Schematics in Hydraulic Brakes.