Condensation in car headlight?

Mercedes18

I’ve noticed condensation inside my driver side headlight on my 2015 Mercedes. I’ve heard this can be due to the outside temperature being colder than the inside hence why the condensation appears. However, I’ve never had this issue before and it’s only just started on one of my headlights. I have used a hairdryer on the outside of the headlight in order to remove the condensation and it all went away. Within minutes it started to build up again. So the next day I tried the same thing with the hair dryer and it all went away only for it to come back. 

Just to confirm there’s no damage, chips or any loose fittings to the headlight to what I can see. Even after lifting the bonnet it all looks sealed and fine. 

Now I would like to know why is this issue occurring and why after heating it up and getting rid of it, it keeps coming back?

I’ve attached a picture for reference. Any help would be much appreciated, thank you. 

facade

There is a tiny leak or crack somewhere, and the headlight has drawn damp air inside. This happens when the warm air inside the headlight cools and contracts

Until you get rid of the damp, it is always going to condense in cold weather. heating it up just evaporates the water making a humid atmosphere inside, as soon as it cools it condenses again.

The headlight needs removing, take out the bulbs and place it in a warm dry area for a couple of days- like your airing cupboard if you are old like me, otherwise it needs go in a sealed tub with a load of dehumidifier crystals.

Once you are sure it is dry inside, seal all around the join between body and glass somehow and refit.

Mercedes18

facade said:

There is a tiny leak or crack somewhere, and the headlight has drawn damp air inside. This happens when the warm air inside the headlight cools and contracts

Until you get rid of the damp, it is always going to condense in cold weather. heating it up just evaporates the water making a humid atmosphere inside, as soon as it cools it condenses again.

The headlight needs removing, take out the bulbs and place it in a warm dry area for a couple of days- like your airing cupboard if you are old like me, otherwise it needs go in a sealed tub with a load of dehumidifier crystals.

Once you are sure it is dry inside, seal all around the join between body and glass somehow and refit.

These are LED headlights and far as I’m aware these are sealed tight with no access points unless the headlight is taken apart and dismantled?

JJC1956

Why not take the car to a Mercedes Dealer or Specialist

Mercedes18

JJC1956 said:

Why not take the car to a Mercedes Dealer or Specialist

I went today but the service department don’t work Sundays. Will be visiting tomorrow 

forgotmyname

If they are sealed how do you change the bulbs or adjust them?  Most have vent tubes also, expanding when hot and
contracting when cold can cause the seams to fail. This would be a bigger problem is they were completely sealed.

Mercedes18

forgotmyname said:

If they are sealed how do you change the bulbs or adjust them?  Most have vent tubes also, expanding when hot and
contracting when cold can cause the seams to fail. This would be a bigger problem is they were completely sealed.

It’s LED a headlight which means there’s no bulbs. The whole headlight unit is part of the LED system.

As far as I’m aware if you remove the headlight unit and dismantle it you would need to reseal it all upon re installing. Could be a bigger job than it seems hence why it may be easier to replace it I think. 

BOWFER

Mercedes18 said:

forgotmyname said:

If they are sealed how do you change the bulbs or adjust them?  Most have vent tubes also, expanding when hot and
contracting when cold can cause the seams to fail. This would be a bigger problem is they were completely sealed.

It’s LED a headlight which means there’s no bulbs. The whole headlight unit is part of the LED system.

As far as I’m aware if you remove the headlight unit and dismantle it you would need to reseal it all upon re installing. Could be a bigger job than it seems hence why it may be easier to replace it I think. 

It might have an LED DRL strip, but I don't think it's an LED headlight (IE not every bulbs in it is LED).
Looks like a projector lens on the left, which will have a Halogen bulb..
It'll be the same for the main beam, halogen.
Have any of the rubber covers over the bulb holes at the back of the light come detached?