Buzz Noise From Rear Speaker After Bulletin 04-08-44-014B - keywords AMP amplifier radio sound speaker UQA

This PI was superseded to update models and model years. Please discard PIT3522B.

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.

1. Inspect the Bare Wires for terminal Integrity.

•	Remove the radio and the C1 connector.

•	Check terminal tension on C1 terminal A5.

•	Remove the AMP connector C1 and C2

•	Check terminal tension on C1 terminal B12

•	Check terminal tension on C2 terminal E

2. 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.

•	Remove the passenger side second row seat.

•	Remove right rear sill plate

•	Lift carpet and follow body harness as it travels along the passenger rear second row seat toward the amplifier.

•	Repair any damaged wires and reroute the harness to prevent future concerns.

3. Remove the console assembly from the vehicle.

•	Refer to the Console Replacement procedure in the Instrument Panel and Console sub-section of the service manual.

•	Remove the rear seat audio module from the console.

•	Remove the console harness, between the in-line to IP connector and the rear seat audio module.

-	B1 (circuit 199, brown) and B5 (circuit 116, yellow)

-	A8 (circuit 599, brown) and B3 (circuit 1547, brown)

-	B2 (circuit 46, dark blue) and B6 (circuit 115, light blue)

-	A9 (circuit 546, dark blue) and A1 (circuit 1946, black)

•	Place the circuits back into their original cavities

•	Install the console harness.

•	Install the rear seat audio module to the console.

•	Install the console assembly into the vehicle. Refer to the Console Replacement procedure in the Instrument Panel and Console sub-section of the service manual.

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.