For 1990-2009 cars

# RADIO NOISE DIAGNOSIS AND REPAIR PROCEDURE

#### SUBJECT: RADIO NOISE DIAGNOSIS AND REPAIR PROCEDURES

#### VEHICLES AFFECTED: 1984-91 C,D,E,K,

This bulletin outlines diagnosis and repair procedures for various radio noises experienced on 1985-1991 DeVilles, Fleetwoods, Eldorados, and Sevilles and 1985-1989 Broughams.

Radio noises can often be categorized by describing the sound heard or the circumstances under which they occur. The trouble trees in this bulletin are broken down by types of noises or where they occur. Noises that do not clearly fall into a noise category should be diagnosed using the "Noise Diagnosis" trouble tree, chart 1. The "Noise Diagnosis" trouble tree is designed to lead to the other trouble trees, if appropriate, or lead directly to the repair.

To begin diagnosis refer to the appropriate trouble tree chart below:

Noise Diagnosis ................. Chart 1 Switch Pops ..................... Chart 2 Whines .......................... Chart 3 Ignition Noise .................. Chart 4 Poor Reception/Static ........... Chart 5 Non-Bose Speakers Noisy ......... Chart 6 Bose Speakers Noisy ............. Chart 7

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.