Recurring condensation in headlight

[Conquistador]

Please don't switch off because it's not Merc but does anybody have any easy methods of removing condensation from the inside of a headlight lens? It only ever happens on the one side.

The headlight units themselves are NOT easy to remove and involves taking about half the engine apart and the wheel off, then peeling back the arch linings even to even change a bulb and I don't particularly want to go drilling tiny holes in the top of the lens or anything either.

Its diffusing the xenon beam on that side so it is quite annoying at night.

Any ideas anybody? Thanks in advance!

 

[Scott_F]

This sort of thing is inevitable with those cheap foreign cars.

 

[ccp]

Previously I've used a hair dryer on the outside of the lens to evaporate the moisture with one of the bulbs removed. A way to improve this would be to blow dry air into the headlight whilst heating the lens.

Chances are the problem will recur because there is a leak letting the moisture in as water which then condenses on the lens.

 

[andy27168]

Hi,
I had one of my 202's fail the MOT for condensation in the headlight (messing up the beam pattern), the tester said for me open the bonnet, place a thick coat over the headlight, and shut the bonnet as a means of holding it there, and turn the headlights on. It steamed a bit but it worked after 10-15 minutes or so, the headlight was clear.

 

[Conquistador]

Hi,
I had one of my 202's fail the MOT for condensation in the headlight (messing up the beam pattern), the tester said for me open the bonnet, place a thick coat over the headlight, and shut the bonnet as a means of holding it there, and turn the headlights on. It steamed a bit but it worked after 10-15 minutes or so, the headlight was clear.

Hmm, sounds plausible but would that work with xenon lights? I didn't think they gave off anywhere near as much heat as halogen bulbs?

 

[grumpyoldgit]

Is the main beam not halogen? Turn that on as well

 

[Conquistador]

Bi-xenon! apparently they give off around 50% less heAt than halogens

The dipped and high beams are made by the one xenon bulb.

 

[Starky]

High beam will still be halogen. I had this on my old BM. Found out that I had lost the cover that protects the housing and seals it, bought a replacement one and all was fine.

 

[Conquistador]

High beam will still be halogen. I had this on my old BM. Found out that I had lost the cover that protects the housing and seals it, bought a replacement one and all was fine.

I'm not sure it is on my Audi. When you switch high beam on, the beam instantly lights up the road where the reflector flicks up (you can even hear a little click from the headlights when it flicks up). The inside lights are 5 little daytime running LEDs.

In contrast, main beam in the bi-xenons on my W221 flicks a reflector up AND makes use of a surprisingly dim halogen light (which are the lenses on the inside of the headlight clusters closest to the grille)

 

[ringway]

I had a similar annoying problem with one of the lights on my Vito.
When I replaced the bulbs (one had blown whilst away on holiday) I discovered that whoever had replaced them before me had snapped one of the lugs on the cover at the rear of the lamp unit. I put it back on as best I could but the light unit condensated badly.

I bought a new rear cover and (in the darkness using a floodlamp to see what I was doing) dried out the light with a hairdryer but the problem persisted. Took cover off and replaced again but no luck. The cost of a new headlight made me try again, so I used a hair dryer again (removed indicator bulb this time) and made doubly sure the cover located perfectly - Job done.

Lesson learnt (not for the first time) make sure you have enough time and good conditions when working.

 

[Bobby Dazzler]

Have a look in your owners manual for the section which covers bulbs. It will tell you which bulb is required for the high beam. If it begins with H, eg H7, then it's halogen.

 

[Starky]

I'm not sure it is on my Audi. When you switch high beam on, the beam instantly lights up the road where the reflector flicks up (you can even hear a little click from the headlights when it flicks up). The inside lights are 5 little daytime running LEDs.

In contrast, main beam in the bi-xenons on my W221 flicks a reflector up AND makes use of a surprisingly dim halogen light (which are the lenses on the inside of the headlight clusters closest to the grille)

My apologies if I'm wrong, but I was under the impression that high beam lights had to be halogen rather than Xenon.

 

[grumpyoldgit]

The inside lights are 5 little daytime running LEDs.

Seems that you need to remove a bulb and get a hairdryer to it then, but that's not going to stop any water ingress in future.

 

[Conquistador]

After a few days of dry weather, it seems to have dried out itself. Result!

Until next time!...