GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1989 🢒 DeVille 🢒 Bulletins 🢒 FRONT/REAR BOSE SPEAKERS OUT OF PHASE (SWITCH WIRES)

FRONT/REAR BOSE SPEAKERS OUT OF PHASE (SWITCH WIRES)

1989 C - CADILLAC DEVILLES AND FLEETWOODS

Some 1989 two-door Cadillac DeVilles and Fleetwoods built between VIN range 200000 and 220000 and equipped with the Bose radio option (UQ4) may exhibit a condition of a noticeable peak in the mid-base frequency response. (The owner may comment of unpleasant audio system base response.) This may be caused by the front/rear Bose speakers being wired out of phase. To repair this condition use the following procedure:

1. Verify that the vehicle is a 1989 DeVille or Fleetwood (two-door) within the VIN range 200000 to 220000.

2. Make sure the radio has been powered off.

3. Unscrew the two speed-nuts to the right rear Bose enclosure.

4. Pull the enclosure down and toward the centre.

5. Peel back the upper right corner of the seat-back trunk trim and pull the Bose speaker connector forward.

6. Disconnect the connector. Verify the enclosure side connector pin-out/wire colours are as shown in Figure 1.

7. If the connector is not wired correctly, back out the + and - audio leads from cavities C and D, and reverse them. (Do not reverse the wires on the vehicle harness side of the connector.)

8. Reconnect the speaker connector.

9. Reinstall the Bose enclosure by sliding into position and pressing on the speed-nuts.

10. Repeat steps 3 through 9 for the left enclosure.


Object Number: 81573 Size: FS

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those 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 a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.