'05-06 models
- Remove the rear seat (see REAR SEAT REMOVAL/INSTALLATION ).
- Disconnect the 22P and 16P connectors from the OnStar control unit.NOTE: All connector views are from wire side of female terminals.
- Inspect the connector and socket terminals to be sure they are all making good contact.
- If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
- If the terminals lock OK, go to step 4.
- Reconnect the connectors to the control unit and make these input tests at the appropriate connector.
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, go to step 5.WIRE CAVITY REFERENCE CHART
Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained A12 BLK Under all conditions Check for voltage to ground: There should be less than 1 V. - Poor ground (G602)
- An open in the wire
A1 WHT Under all conditions Check for voltage to ground: There should be less than 1 V. - Blown No. 5 (7.5A) fuse in the driver's under-dash fuse/relay box
- An open in the wire
A2 YEL Ignition switch ON (II) Check for voltage to ground: There should be battery voltage. - Blown No. 21 (10A) fuse in the driver's under-dash fuse/relay box
- An open in the wire
A13 PUR Ignition switch in ACC (1) Check for voltage to ground: There should be battery voltage. - Blown No. 32 (10A) fuse in the driver's under-dash fuse/relay box
- An open in the wire
B10 GRY Under all conditions Check for voltage to ground: There should be less than 1 V. An open in the wire B13 GRY Under all conditions Check for voltage to ground: There should be less than 1 V. An open in the wire B14 YEL Under all conditions Check for voltage to ground: There should be less than 1 V. An open in the wire B1 GRN Ignition switch in ACC (1). OnStar "DOT" button pushed. Speak into the microphone. Check for voltage to ground: There should be about 4 V. - Faulty OnStar buttons and microphone
- An open in the wire
B9 RED Under all conditions Check for voltage to ground: There should be less than 1 V. - Faulty OnStar buttons and microphone
- An open in the wire
B4 GRN OnStar "DOT" button pushed and human advisor voice comes on. Check for voltage between the B4 terminal and stereo amplifier connector C (23P) No. 12 terminal: There should be less than 1 V. - Faulty stereo amplifier
- Faulty speaker
- An open in the wire
B12 RED OnStar "DOT" button pushed and human advisor voice comes on. Check for voltage between the B4 terminal and stereo amplifier connector C (23P) No. 13 terminal: There should be less than 1 V. - Faulty stereo amplifier
- Faulty speaker
- An open in the wire
- Disconnect the 22P and 16P connectors from the OnStar control unit, and make these input tests at the appropriate connector.
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, the control unit must be faulty; replace it.WIRE CAVITY REFERENCE CHART
Cavity Wire Test conditions Test; Desired result Possible cause if result is not obtained A3 LT GRN Under all conditions Check for continuity between the A3 terminal and driver's under-dash fuse/relay box connector G (6P) No. 1 terminal:
There should be continuity.An open in the wire A14 YEL Under all conditions Check for continuity between the A14 terminal and multiplex integrated control unit connector P (30P) No. 21 terminal:
There should be continuity.An open in the wire B16 GRN Under all conditions Check for continuity between the B16 terminal and audio unit connector B (32P) No. 8 terminal:
There should be continuity.An open in the wire B6 LT BLU Under all conditions Check for continuity between the B6 terminal and roof console connector (28P) No. 1 terminal:
There should be continuity.An open in the wire B15 BRN Under all conditions Check for continuity between the B15 terminal and roof console connector (28P) No. 16 terminal:
There should be continuity.An open in the wire B7 ORN Under all conditions Check for continuity between the B7 terminal and roof console connector (28P)No. 15 terminal:
There should be continuity.An open in the wire