Condensation in fog light

[MattHGR]

Hi all,

Upgraded to led fogs a couple of weeks ago, and started noticing some condensation appearing in one of the fog light housings.
Front passenger side is my issue.

Obviously the first thing I jumped to was that the new bulb fitting must not be tight, so I checked the thing was locked in place and even put some electrical tape around the fitting to make sure.

Today, I can see more condensation in the fog..

It has happened 4 times in the last 2 weeks.

Anybody else seen this, and does anyone have any ideas why it is happening ?
Maybe a breather hole has been blocked. Does anyone know where this can be found ?

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[monkeyhanger]

LEDs kick out next to no heat (which is why they're so efficient). Moist air gets in to the housing and the bulbs don't give out enough heat when used as cornering lights for it to evaporate. Halogens do have their uses.

[Simonz]

Based on this unless the housing is 100% air tight and dried out any remaining moisture will cause issues. Maybe try letting it dry out fully, leaving it open plus hairdryer then refit and seal it up. You could go as far as silicone sealant if you're confident it won't need dismantling for a long while due to long life of LED bulbs.

[shaunrazer]

Put a few packs of the Silica gels that you get in the back. The ones you get with new shoes, trainers etc.

[MattHGR]

Put a few packs of the Silica gels that you get in the back. The ones you get with new shoes, trainers etc.

Considered doing that, but had a lovely dry day today. Had the bulb hanging out of the housing and the car pointing into the sun for at least 6 or 7 hours.
Should hopefully be all dried out now, so I've screwed the bulb back in whilst it cools off in the evening.

If I think there's still some liquid in there I'll give the silica idea a go !


The bulb seal is very tight. No wiggle room that's for sure. And I put electrical rubber tape over the seal too and still got condensation.

Hoping it was just residual liquid that kept coming back, but if not I think maybe the housing has a gap somewhere.
Washing the car has made it condense, and so did driving with spray from the car in front.
It didn't seem to be humid air, but liquid hitting the housing was getting in.


Time will tell.


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[mjsaville]

I've had a problem previously with fog lights on an Audi A5 when I retro fitted whiter ones to match the Xenon headlights. Turned out the bulbs were poor quality and their built in water seals were like a sieve !!

[SRGTD]

No doubt bulb technology has advanced significantly over the years and I can understand why some owners may want to change their front fogs to LED if aesthetics is important to them. However, there was a school of thought that bulbs emitting a yellower light were more effective as fog lights than a bright white light, but maybe that’s not longer the case? I can remember in the 1970’s / 1980’s when it was the trend to tint the lenses of fog lights yellow, so creating a very obvious colour mismatch between fog lights and headlights (and yellow fog lights used to be mandatory in France).

I know the fogs / cornering lights in my (previous generation) GTI don’t match the colour of the LED headlamps or DRL’s, but that doesn’t bother me - and that’s from someone who suffers from car OCD! . I‘ve rarely needed use the fog lights anyway - maybe a couple of times in nearly 4.5 years of ownership. And the cornering lights are only on for a few seconds at a time, so the mismatch of yellow-ish halogen bulbs and LED headlamps is fine with me.

For those forum members who have driven in night time foggy conditions with both the original halogen fog light bulbs and LED replacements, I’d be interested to hear your views on how the LED’s perform compared to the original factory fit bulbs.

[ShockingIce]

No doubt bulb technology has advanced significantly over the years and I can understand why some owners may want to change their front fogs to LED if aesthetics is important to them. However, there was a school of thought that bulbs emitting a yellower light were more effective as fog lights than a bright white light, but maybe that’s not longer the case? [emoji848] I can remember in the 1970’s / 1980’s when it was the trend to tint the lenses of fog lights yellow, so creating a very obvious colour mismatch between fog lights and headlights (and yellow fog lights used to be mandatory in France).

I know the fogs / cornering lights in my (previous generation) GTI don’t match the colour of the LED headlamps or DRL’s, but that doesn’t bother me - and that’s from someone who suffers from car OCD! [emoji16]. I‘ve rarely needed use the fog lights anyway - maybe a couple of times in nearly 4.5 years of ownership. And the cornering lights are only on for a few seconds at a time, so the mismatch of yellow-ish halogen bulbs and LED headlamps is fine with me.

For those forum members who have driven in night time foggy conditions with both the original halogen fog light bulbs and LED replacements, I’d be interested to hear your views on how the LED’s perform compared to the original factory fit bulbs.

This is something I would actually like to know too. You would think that LED’s were better in every situation, especially nowadays but bulbs have their uses too!


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[monkeyhanger]

It's a fact that yellow light cuts through fog better than white light. If you put white LEDs in your fog light surrounds, they won't work well as actual foglights.

I've only intentionally used my front fogs twice in 4 years, because only twice in that time has my visibility been reduced to less than 100m.

You'll get far more use from the foglights as dynamic cornering lights than for seeing through fog. Some cars don't even have front fogs - my Golf R had air intakes where the foglights should be. My Audi A4 has Audi pre-sence radar sensors where the foglights should be.

[MattHGR]

Update on the fog light issue:
Washed the car today after ensuring the unit was bone dry.
Slight bit of condensation and water build up appeared on the back of the glass.
After closer inspection, it appears the fog light housing behind the bumper is being flooded with water.
Water is dripping on the back of the bulb, and the housing, including where I believe the top breather hole to be.
On the drivers side, a little bit of water dribbles on the top of the housing, but not near the breather hole or the bulb.

There's a plastic tray above the fog light housing on both sides, and I'm thinking the passenger side one is either clogged or bent, causing the run of water to hit the fog housing.



Has anyone here removed the factory LED headlights from there car yet ? If so, is it easy? This water run off tray appears to be below the headlight unit so I might have to dismantle and have a look.

Cheers,
Matt

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