Body Control System: Overview GMC Savana H2500

Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. 6. This step tests for battery voltage on the signal circuits that are not required.
2. 7. This step tests for no battery voltage on the required signal circuits.
3. 8. If any ignition switch parameters that should be inactive in the present ignition switch position are active, 2 ignition switch signal circuits may be shorted together.
4. 9. This step eliminates open circuits as the cause of the malfunction.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

1. Remove the right side knee bolster trim panel. Refer to «KNEE BOLSTER REPLACEMENT - RIGHT»(ref-176310-S08419790372005050300000) .
2. Disconnect the electrical connectors (2) from the Body Control Module (BCM) (1).
3. Release the tabs (2) retaining the BCM (1) to the bracket.
4. Remove the BCM (1) from the vehicle.

Scheme 7

Scheme 8

Scheme 9

1. Install the BCM (1) into the bracket. Ensure the BCM (1) is engaged in the bracket, under the retaining tabs (2).
2. Connect the electrical connectors (2) to the BCM (1).
3. Install the right side knee bolster trim panel. Refer to «KNEE BOLSTER REPLACEMENT - RIGHT»(ref-176310-S08419790372005050300000) .
4. If the BCM has been replaced the module will need to be programed. Program the BCM. Refer to «Body Control Module (BCM) Programming/RPO Configuration»(ref-176309-S05136625442005050300000) .

Fail-safe Operation

Since the operation of the vehicle systems depends on the power mode, there is a fail-safe plan in place should the BCM fail to send a power mode message. The fail-safe plan covers modules with discrete ignition signal inputs as well as those modules using exclusively serial data control of power mode.