2005 Mercedes Benz CLK 320 Technical Service Bulletin # P-82_10-419 Date: 041230

Lighting - Condensation in Headlamps
Date: December 30, 2004
Order No.: P-B-82.10/419
Supersedes:
Group: 82
SUBJECT:
Model 170, 171, 203, 208, 209, 210, 211, 215, 220 and 230
2000 Mercedes Benz CLK 320 (208.365) V6-3.2L (112.940) Page 180
Moisture in Headlamp(s)
Note:
For Information Only!
If you receive customer reports in the above model vehicles moisture or water inside the headlamp(s), please offer the following explanations.
Surfaces fog up whenever they are cold and come in contact with warmer, humid air. An example of this is the mirror in the bathroom. It often fogs
up after showering because it comes in contact with the warm humid air from the shower enclosure. The same thing occurs to the headlamps.
Moisture or water on or around the engine evaporates and this vapor condenses on the coldest surface in the surrounding area. This is frequently the
headlamps since they are frequently in contact with cold air or cold rain.
The headlamps have ventilation holes on the back. Without these holes, pressure would be produced when the headlamps are switched on damaging
the headlamps.
A malfunctioning headlamp can be identified as follows. As a prerequisite, the headlamp(s) must be fogged up when the vehicle is brought into the
workshop.

1. Is there a puddle of water inside the headlamp? If yes, the headlamp is malfunctioning and should be replaced.


2. Does the headlamp show signs of external damage? If yes, the headlamp is malfunctioning and must be replaced. This is not covered by

warranty.
3. If there is only an appearance of moisture on the inside surfaces of the headlamp and there is no external damage, the headlamp is then okay.
Note:
If the owner complains of fogging but the fogging is not present when the car is brought in, then this is normal and not an indication of any
malfunction.
Clearing fogged headlamps and/or fog lamps.

1. Drive the car into the workshop and connect the exhaust extractor. In dry weather, this can also be performed outside.


2. Start the engine and switch on the low beam + high beam, front fog lamps and hazard warning lamps.


3. Leave the vehicle in this state for 20 minutes.


4. Switch off all lights and the engine.


5. If the headlamps and/or fog lamps are completely clear, the observed fogging or water is normal. If not, the headlamp or fog lamp is not