INOPERATIVE SOFT TOP REAR WINDOW DEFOGGER

MODELS AFFECTED: 1987 ALLANTE

Some 1987 Allantes may experience an inoperative soft top rear window defogger, caused by a short to ground on circuit 192. If this condition is experienced on an Allante before breakpoint 100485, check for a short between the soft top rear window frame and the defogger grid as follows:

1. Remove hard top and raise soft top. Leave soft top rear window in its inverted position.

2. Start engine and turn rear defogger on.

3. Disconnect the passenger side grid connector.

4. Check voltage from the grid connector to ground on the passenger side window frame pivot. This reading should be between 14.0 and 14.4 volts.

5. Reconnect the grid connector and check voltage from the grid connector to ground on the window frame pivot again. This reading should be 1.5 volts less than the previous reading or between 12.5 and 12.9 volts.

6. If the voltage drop is greater than 1.5 volts, proceed to step 7.

7. Install shims between the window frame and glass on the passenger side as follows:

A. Insert a small screwdriver or putty knife between the window frame and the glass on the passenger side.

NOTICE: Do not slide blade across defogger grid material.

B. Lift up frame and slide shims into place. Shims should be approximately 1/4" wide by 2" long by .02" thick and made of a thin clear insulating material such as acetate.

C. Shims should be installed at every other grid line starting with the bottom grid and between the rear defogger terminal and the window frame.

D. Repeat the voltage checks above (steps 2 through 6).

For warranty purposes, use labor operation T6203 at 1.1 hours.

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.