Lamp unit fogged/droplets forming

2010 Mercedes Benz Truck GL 350 BLUETEC (164.825) V6-3.0L DSL Turbo (642.820)
Vehicle: All Technical Service Bulletins
Lighting - Headlamp Unit Fogged/Droplets Forming
Lamp unit fogged/droplets forming
Topic number LI82.10-P-051769
Version 2
Design group 82.10 Exterior lights
Date 09-05-2012
Validity All models
Reason for change New repair method
Complaint
Lamp unit fogged or droplets forming.
Cause
Due to the vent openings, the lamp unit is an "open system".
This means that acidic gases, moisture, dirt and exhaust gases can penetrate it.
This can result in deposits on the diffuser and lens.
Remedy
Check housing cover of lamp unit for natural fogging or dew as per LI82.10-P-050139.
1. If a reduction in the degree of fogging is visible, the pressure compensation membrane can be inserted after complete evaporation of the dew.
2. If no reduction in the degree of fogging is visible, the lamp unit is defective and must be replaced.
However, the cover with the pressure compensation membrane should also be attached in this case.
Note:
Residual fogging is possible due to the laws of physics and is OK.
Fogging does not impair the functionality or the service life of the lamp unit.
Pressure compensation membranes should always be used on both lamp units.
Attach housing cover with pressure compensation membrane:
1. Remove lamp unit
2. Remove all vent opening grommets.
3. Seal vent openings with sealing profile.
Important:
All openings must be sealed carefully for the pressure compensation membrane to work properly!
4. Insert housing cover with pressure compensation membrane.
5. Install lamp unit.
W/S 204 Attach pressure compensation membrane to housing cover of lamp unit:
1. Remove lamp unit
2. Remove all vent opening grommets.
3. Seal vent openings with sealing profile.
Important:
All openings must be sealed carefully for the pressure compensation membrane to work properly!
2010 Mercedes Benz Truck GL 350 BLUETEC (164.825) V6-3.0L DSL Turbo (642.820)
4. Remove housing cover of lamp unit.
5. Drill and deburr three holes in the housing cover of the lamp unit as per the template (see attachment).
6. Glue on the pressure compensation membrane.
Bonding note:
The substrate must be free of dust and grease.
7. Reattach housing cover of lamp unit.
8. Install lamp unit.
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Operation numbers/damage codes