GM Service Manual Online
For 1990-2009 cars only

REDESIGNED RADIO CONTROLS SWITCH REPAIR

Model and Year: 1989 C/K 1, 2, 3 WITH U58 OR U69 OPTIONS

TO: ALL CHEVROLET DEALERS

The balance, treble, bass and fade buttons on the upgrade radios in our 1988-89 C/K models each have three functions:

1. Centering function. Press the button in the center and feature sets in a neutral position.

2. Increase function. Press + or > and the feature increases.

3. Decrease function. Press - or < and the feature decreases.

On 1988 model trucks the increase and decrease indicators were centered on the ends of the buttons; however, the increase and decrease switches are located under the corners of the buttons. Starting in calendar year 1989, the indicators + or >, - or < were relocated on the corners of the buttons for more positive operator input on the bass, treble, balance and fade buttons. Customers inquiring about radio push button sensitivity should be advised of the facts above. Radios should always be checked to verify improper function before removal for repair.

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.