Rear Door Locks Inoperative, SIR Lamp, Radio/OnStar Has Poor Sound Quality - keywords actuator audio B0092 lock noise radio rear SDM SIR sound speaker

This PI has been revised to add pinched harness information under passenger front seat at passenger front seat rear mount bracket. Also updated model years to include 2006. Please discard PIT3214.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Rear door locks inoperative, SIR lamp, radio sound quality and/or poor OnStar sound quality, rear speakers muted or will not mute, possible DTC B0092. There are 2 possible areas of concern for the issues listed. 1st possible cause of these symptoms is a loose connection at connector C304, a 40-way connector mounted under the left rear seat. 2nd possible concern is a pinched harness at the passenger side rear seat mounting bracket that secures the seat to the floor. This concern only applies to short wheelbase vehicles.

1. Inspect C304. All terminal connections should be checked in this connector to confirm terminal integrity. Note: When servicing this connector special care should be made not to damage other terminals. Fully seat the connector squarely with both hands, and then latch the locking portion of the connector (CPA). Do not use the lock mechanism on the connector to pull the connector halves together as this may cause more bent terminals and poor connections.
2. If the rear speakers are muted or will not mute, check for circuit 493 for unwanted ground or short to voltage under the passenger side rear seat mounting bracket. This would only apply to short wheelbase vehicles.

Note: (Doc# 1617261) Circuit 493 is the rear seat audio enable signal from the Radio to the Amplifier. When the RSE is turned on 12 volts is sent out from the radio (circuit 493) to the Amplifier (UQA). This mutes the rear speakers. When the RSE is turned off there is 0 volts on circuit 493. The rear speakers are then back on.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.