WHINE OVER RADIO SPEAKERS WITH HEADLIGHTS ON

VEHICLES AFFECTED: 1986-1988 E/K

Some 1986-1988 Eldorados and Sevilles may experience a condition of a whine over the radio speakers with the headlights on. This can occur with any sound system.

This condition may be caused by noise entering the radio on one of the dimming or illumination circuits. The volume of the whine can be increased and decreased by using the interior dimming switch thumbwheel. The noise will almost be eliminated in the "full dim" position.

To repair this condition use the following procedure below (refer to Section 8A, cell 150 of the Service Information Manual for circuit and connector references):

1. Turn on both the radio and the headlights to verify the condition.

2. The black wire in radio connector C1 on 1986 vehicles or C4 on 1987-1988 vehicles, is circuit 804, a ground. This wire should be backed out of cavity 1 of the connector and taped to the harness to prevent rattling. Attach one end of a braided ground strap, P/N 12016624, to the radio chassis, refer to Figure 1. The other end should be taken to ground at one of the steering column mounting bolts. Check if the whine has been eliminated. If not, proceed to step 3.

3. Install noise filter P/N 1224205 at the radio connector in circuits 8 a gray wire, 588 a brown wire, and 724 a yellow and purple wire. This filter is a 3 lead, in-line filter. The ends of two of the leads are stripped, while the third lead ends with an eyelet. With the key off, cut each of the circuits. Strip the ends of each half of each circuit. Solder one of the stripped filter leads to each half of the cut circuit. These solder joints should be taped using electrical tape. The third filter lead, with the eyelet, should be attached to the radio chassis. Turn headlights and radio on and check if the whine has been eliminated. If not, continue to step 4.

4. If the whine has not been eliminated, continue with noise diagnosis outlined in Section 8A, cell 150 of the 1987-1988 Service Information Manual. This information is applicable to 1986 vehicles.

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.