GLC headlight - lots water condensation inside ??




Passenger front headlight is ;growing water’ inside unit. Worried electrical will impact and light motors will fail.
Any experience in this Forum ? Someone said unit may have a drain hole or vent that could be blocked ?
Unit seems well bolted in and it may be major surgery to remove front bar or supports to take headlight out - any suggestions or instructions?photos appreciated.
Front lens does not appear to be cracked anywhere.




But it would need removing to assess.
$300Au labour per hour, 3 hour charge to remove front bumper and replace, plus time to inspect unit, if replaced another 30 min to recalibrate 3 x motors in unit.
So around $1200Au to look and replace - if warranty denied, add cost of new headlight unit ?? Could be $4000Au ?
Sounds expensive - will investigate further with my Dealership.
But it would need removing to assess.
$300Au labour per hour, 3 hour charge to remove front bumper and replace, plus time to inspect unit, if replaced another 30 min to recalibrate 3 x motors in unit.
So around $1200Au to look and replace - if warranty denied, add cost of new headlight unit ?? Could be $4000Au ?
Sounds expensive - will investigate further with my Dealership.
But it would need removing to assess.
$300Au labour per hour, 3 hour charge to remove front bumper and replace, plus time to inspect unit, if replaced another 30 min to recalibrate 3 x motors in unit.
So around $1200Au to look and replace - if warranty denied, add cost of new headlight unit ?? Could be $4000Au ?
Sounds expensive - will investigate further with my Dealership.
Mine wasn't as bad as yours but Mercedes has a procedure for this headlight condensation issue, which is to insert silica gel bags under warranty. Everybody knows that's a temporary fix, but that's what MB does. If that still doesn't fix the issue, they will then replace the headlights under warranty. However, I read online that owners of S-class in the US have had them replaced twice or even thrice but eventually condensation came back.
If yours is still under warranty, diagnosis should be conducted free of charge. This is a fairy common issue not just with Mercedes anyway.
Last edited by pussgalore; May 14, 2023 at 07:07 PM.
If yours is still under warranty, diagnosis should be conducted free of charge. This is a fairy common issue not just with Mercedes anyway.
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I didn't want mine replaced with the new ones either because they could be worse than the original.
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I didn't want mine replaced with the new ones either because they could be worse than the original.
How to fix fogging of headlamps:
1. Drill 2 5mm holes either end of the top of the headlamp unit so that the holes are open to the inside of the light cavity.
2. Carefully warm the front of the light with a heat gun for a few minuets.
3. With a portable battery air pump type used for air beds fitted with a suitable narrow nozzle (mine is a Pumtech DP6) put the nozzle onto one of the holes and turn on and hold for some time.
4. Check air coming out of the other hole.
5. Taking care, play the heat gun into the air pump inlet - this all may take a while depending on how bad your fogging is.
6. When moisture gone, tape over the holes with good quality tape - you will probably need to repeat above as more moisture gets into the light from the poor seals.
Happy motoring



