Bose Noise

tec3001 · September 4, 2005

I need some help with the Bose system in my 05 Envoy Denali. When my engine is running, I hear a high pitched noise coming from my rear door speakers. It seems like the noise is only in the rear speakers, when I fade to the front only, the noise is still in the rear speakers. I also noticed that when the rear audio control is used the rear speakers cut off and the noise is gone. When the engine is off all is good.

Does anyone have any ideas where I can start to fix this annoying problem? I have been to the dealer 3 times with no luck.

GM-Tech · September 4, 2005

First, they should perform the following bulletin (even if it doesn't exactly describe your problem). After they do this, there's a PI (preliminary information) bulletin they should follow. I'll include that too.

BTW, these were found with about a 1 minute search in our Service Information, which your dealer should also have found... and maybe did and already tried.

FIRST THE BULLETIN

Buzz Type Noise Coming From Rear Speakers (Relocate Transfer Case Module Ground) #04-08-44-014B - (Oct 19, 2004)

2004-2005 Buick Rainier

2004-2005 Chevrolet TrailBlazer, TrailBlazer EXT

2004-2005 GMC Envoy, Envoy XL, Envoy XUV

2004 Oldsmobile Bravada

with Speaker System Premium Performance Enhanced (Bose®) Audio (RPO UQA) and A4WD/AWD

This bulletin is being revised to provide an updated service procedure and new warranty information. Please discard Corporate Bulletin Number 04-08-44-014A (Section 08 -- Body and Accessories).

Condition

Some customers may comment on a buzz type noise heard through the rear speakers. This noise can only be heard when the radio is on, volume low and while driving in A4WD/AWD mode. The noise USUALLY occurs above 32 km/h (20 mph) and is related to the active transfer case operation.

Correction

Important: This procedure will only correct the noise related to transfer case operation. It will not correct the speed sensitive whine type noise, commonly referred to as alternator whine.

Perform the following procedure to reduce the rear speaker buzz noise caused by the active transfer case.

Remove the left side IP closeout panel.

Remove the transfer case control module and mounting bracket from the IP mag beam.

Disconnect the C3 connector from the transfer case control module.

Remove the wire and terminal from cavity A (circuit 2250) from C3 connector. Tape back.

Construct a new ground wire using terminals P/N 12047767 and P/N 12089496. Route this wire through the grommet from the IP out to the engine compartment.

Install the new ring terminal onto ground stud (G105) located on the bulkhead just above the brake booster.

Install the new terminal into cavity A of connector C3.

Connect the C3 connector to the transfer case control module.

Install the transfer case control module and mounting bracket to the IP mag beam.

Install the left side IP closeout panel.

Part Information

Part Number

Description

Qty

Material Allowance

12047767

Terminal

1

-

12089496

Ring Terminal

1

-

Bulk 14 Gauge Wire

-

$2.00

The terminals are included in Packard Terminal Repair Kit J 38125-A or available for ordering by calling 1-800-GM-TOOLS.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

N9517 *

Ground (T/C Module) - Relocate

0.4 hr

*This is a unique labor operation number for use only with this bulletin. This number will not be published in the Labor Time Guide.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

HERE'S THE P.I. (which specifically says to perform the above bulletin first)

Buzz Noise from Rear Speakers after Bulletin 04-08-44-014B - keywords AMP amplifier radio sound speaker UQA #PIT3522A - (Jul 13, 2005)

2004-2005 Chevrolet TrailBlazer, TrailBlazer EXT

2004-2005 GMC Envoy, Envoy XL, Envoy XUV

2004 Oldsmobile Bravada

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

Condition/Concern:

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 a 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.

Recommendation/Instructions:

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.

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, running between the in-line to IP connector and the rear seat audio module.

Remove the following circuits from the in-line to IP connector and twist together (minimum of 1 twist per inch) in 4 separate pairs.

- 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.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

tec3001 · September 4, 2005

The dealer did apply the Bulletin, but that did not help. The PI you listed sound exactly like the problem I am having. I am going to discuss this with them this week.

Thanks for the great information.