CD/Radio - Inoperative, Steering Wheel Controls Lock Up

NUMBER: 93-T-74

CORP.REF.NO: 339006

DATE: July 1993

SECTION: 8A

SUBJECT:
INTERMITTENT OR INOPERATIVE CD OR RADIO OPERATION, OR SWC (STEERING WHEEL CONTROLS) LOCKUP - ADD LIGHT SHIELD

MODELS/YEARS:
1989-93 CUTLASS SUPREME
W/SWC (RPO UK3)

CONDITION:
1989-93 Cutlass Supreme models with a radio and SWC (RPO Code UK3) may have one or more of several intermittent conditions. These include:

^ The CD, radio, or tape player may become inoperative.
^ The radio or SWC's could lock up.
^ Any radio function could happen at random, without the customer pushing any buttons. For example, the volume may go up or down by itself.

This condition is most common during CD player operation, but could also happen while using the tape player or the radio. It will occur only during daylight, usually in bright sunlight and while turning. The radio can be returned to normal operation by cycling the ignition switch, or sometimes by turning the radio power off and on.

CAUSE:
The SWC operates by optics in the cancel cam and the turn signal switch. The steering column has a square outer cover. Under some conditions of bright daylight, and with the wheel turned at about 45 degrees, light can enter the column between the wheel and the top of the column. This light can be incorrectly interpreted as a command from the SWC, causing the conditions described above. A steering column light shield was added in production after VIN PD346219 to correct this condition.

CORRECTION:
To determine if the light leak is causing the customer's condition, shine a bright light into the edge of the column, while turning the wheel. Flash the light to duplicate a SWC command. If the vehicle has a CD player, playing a CD may help to duplicate the condition, since the SWC commands are sent to the radio every second.

If the condition is duplicated by the above test, install a light shield, P/N 26041364, on the cancel cam. Instructions are included in the package. This shield will prevent any stray light from reaching the optics.

If the above test does not duplicate the condition, use normal service manual diagnostic procedures.

PARTS INFORMATION:
Parts are currently available from GMSPO.

WARRANTY INFORMATION:
Use current Labor Time Guide.