Subject: | Buzz Noise From Rear Speakers After Bulletin 04-08-44-014B |
Models: | 2004-2007 Buick Rainier |
2004-2007 Chevrolet TrailBlazer, TrailBlazer EXT, Trailblazer SS |
2004-2007 GMC Envoy, Envoy XL, Envoy XUV and Envoy Denali |
2004 Oldsmobile Bravada |
2005-2007 Saab 97x |
This PI was superceded to advise that bulletin 04-08-44-014B listed in this PI applies to 2004-2005 vehicles only. Please discard PIT3522D.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Rear speaker noise on vehicles with rear seat audio controls (RSA) and Bose amplifier. This noise can be produced from a variety of high load or PWM controlled electrical components (rear window defroster, heated seats...) but usually can be identified as an whine noise related to engine speed (generator electrical feedback). This condition can be verified by turning the RSA on (rear speakers off) and the noise should go away. If the noise is the same the root cause most likely exists elsewhere and additional diagnosis is necessary.
Perform the following procedure to reduce the rear speaker buzz noise AFTER all low level and high level circuit integrity has been verified. For example, it is possible for the system to produce audio output to the speakers even if a (-) circuit has an open. However it will most likely produce undesirable noise in this condition.
Note: Bulletin 04-08-44-014B applies to 2004-2005 vehicles only. The Transfer Case Control Module ground has been relocted on all 2006 and newer vehicles. The information may be helpful on 2006 and newer vehicles.
Important: Prior to moving forward with the directions below, all 2008 model schematic refer to all connectors as the letter "X" then the connector number. The letter X is the new global term for connector. Since this PI address 2008 and prior, the connector number will be written both with the letter C and the letter X.
Note: After each step below, re-evaluate the concern. If the concern is repaired, there is no need to continue with additional steps.
A. Check for damaged harness under the passenger rear 2nd row seat. This step applies to short wheel base vehicles ONLY equipped with AMP RPO UQA.
B. Remove the AMP connector. On short wheel base vehicles, the AMP is located behind the right rear 1/4 trim panel. Removal of the trim is needed to access the AMP. On extended wheel base vehicles, the AMP is located on the left rear 1/4 trim panel. Remove the access panel in the left rear trim and locate the AMP connector.
C. Inspect the Bare Wires for terminal Integrity.
- Check terminal tension on C1 or X1 terminal A5. Use test probe J-35616-6 (BN). Replace any loose or damaged terminals as needed.
- Check terminal tension on C1 or X1 terminal B12. Use test probe J-35616-6 (BN). Replace any loose or damaged terminals as needed.
- Check terminal tension on C2 or X2 terminal E. Use test probe J-35616-6 (BN). Replace any loose or damaged terminals as needed.
D. Remove the center console assembly from the vehicle. Refer to the Console Replacement procedure in the Instrument Panel and Console sub-section of the service manual.
E. Locate the C304 or X304 connector. This is located under the second row rear seat on the driver's side. There is a cut out in the carpet were this connector can be accessed.
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.