For 1990-2009 cars

# COMPOSITE HEADLAMP CONDENSATION-REPAIR PROCEDURE

#### SUBJECT COMPOSITE HEADLAMP CONDENSATION - REPAIR PROCEDURE

#### MODELS/YEARS 1991 NINETY EIGHT ----------------------------------------------------------------------------

Some 1991 Ninety Eight models may exhibit condensation on the inside of the composite headlamp lens. This can be caused by a forced water spray (e.g. car wash) entering the upper vent hole located on the in-board end of the headlamp.

#### Correction:

----------- 1. Remove the headlamp from the vehicle per the instructions for bulb replacement.

2. Remove the two bulbs (high and low beams), being careful not to allow any oil or grease to get on the bulb glass or base.

3. With the rear of the lamp facing you, inject compressed air into the upper vent to blow any residual water into the lamp cavity.

4. With the lamp in the same position, inject compressed air into each bulb hole towards the inside of the lens to drive any water to the bottom of the lamp where it can then run out of the bottom vent.

5. With a heat gun, turned on "low", blow WARM (not hot) air into one of the bulb holes. Allow the warm air to pass through the one bulb hole and out the other until all signs of moisture have left the lamp.

#### Note: Do not place the heat gun too close to the lamp, as the lens may get too hot and become damaged or melt.

6. Allow the lamp to cool to ambient or room temperature WITHOUT the bulbs being installed.

7. Plug the upper vent hole with a small amount of RTV. Be sure to force it into the hole leaving a small mound on the outside to provide a permanent seal.

8. Allow the RTV to cure for at least 15 minutes before the bulbs are installed and the lamp is reinstalled on the vehicle.

9. Reinstall the headlamp to the vehicle. Light both low and high beams to insure proper electrical connection.

#### Note: Any Service Replacement Headlamps being installed that are dated prior to July 25,1991, should be repaired, as described above, by plugging the upper vent hole with RTV before vehicle installation.

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.