Condensation in rear light s

[crazylegs]

Hi all,

The rear light cluster on my Chimaera has a cloud of what looks like condensation in the rear lights. Has anybody else experienced this and know how to go about fixing it?

I tried placing some silica gel to see if this cleared up the moisture, but it was only in the boot near the lights so probably wouldn't have much effect. Either way, it hasn't worked.

Any help much appreciated...

[tvrbob]

Several of us have had this. The trick is to stop water gathering in there in the first place. Sealing it will stop most of your problem but it will return over time. I, and several others have drilled an 1/8 hole at the lowest point. Water that does gather can then get out and it allows the space to breath. Since I did this I've never had any problem.

[dilbert]

I think there are two approaches.

You can seal it up completely, or you can ventilate it. Inbetween is a pain.

If you seal it up, you trap air and moisture at the point when you close it. If the air was humid when you sealed it, as the temperature changes the water condenses, and evaporates, but cant get out.

If you ventilate, you end up balancing the humidity. If it's foggy out it'll be foggy in (so to say).

If the seals look good, a tip is to assemble on a nice hot dry day. Another way is to use a hairdryer as you put the thing together.

[tvrbob]

Agreed but beware of the hairdryer idea. I know it seams like you are drying the moisture out. The fact is that the hotter the air the more moisture it can contain. Trap this in and let it cool down again and, hay presto, it deposits its contained moisture back onto the cover. Cold dry air is what you actually need to trap in there.

[chimleic]

Would drilling not lead to further damp risk to the electics?

[dilbert]

tvrbob said:

Agreed but beware of the hairdryer idea. I know it seams like you are drying the moisture out. The fact is that the hotter the air the more moisture it can contain. Trap this in and let it cool down again and, hay presto, it deposits its contained moisture back onto the cover. Cold dry air is what you actually need to trap in there.

Agreed.

But I have no easy suggestion as to how to make cold dry air!

If your workshop isn't foggy, however, and you allow a reasonable ammount of hot air from the environment to pass through the lamp housing, any moisture trapped in the housing will evaporate.

I suppose one solution might be to use a high pressure airline with a water separator.

I ought to also say that the hairdryer approach has solved the problem for me before.

>> Edited by dilbert on Sunday 20th February 14:11

[tvrbob]

chimleic said:

Would drilling not lead to further damp risk to the electics?

Not at all. Many vehicle lights have vents at the bottom. Usually it's a slot between the seal material and the cover so it's hidden from view. Water can't get in even from a hosepipe. The only way for water to get through the vent is as water vapour. Air inside the cover is generally the same temperature or hotter than the air outside (green house effect) so the balance can only cause condensation on the outside.

[chimleic]

Sounds like a good option then. Has anyone got photos/directions - natually I am a but twitchy about taking a drill to my car! LOL

[CHRIS43]

Suffered the same problem about a year ago and, on the combined advice of PHers, drilled 2 very small holes, one in each rear lamp and voila! all is now ok!!

[chimleic]

Sounds like the best solution then! Any pics or greater detail of where to drill would be much appreciated as I have damp in one of my rear units. Ta!

[crazylegs]

chimleic said:

Sounds like the best solution then! Any pics or greater detail of where to drill would be much appreciated as I have damp in one of my rear units. Ta!

I'd be interested in this before I take to my car with a drill too!

[steve1c]

Before you drill, put a strip (or even two) of masking tape on the chosen spot and drill through this. It will help stop the drill slippng and scratching the lense.

[tvrbob]

I don't have pictures but it really is simple. Sit behind the light so your eyes are in line with the bottom. Mark the lowest point where the bodywork curves away from the cover. That's where you drill. Start with a 1/16th drill bit and make sure its sharp. Leave it like that for a while and if your problem goes away, leave it like that. If not then with a sharp 1/8th drill bit open the hole up. Don't go bigger the 1/8th and all will be well.

[chimleic]

So, drilling from the outside into the rear lights? Not from the inside into the cluster from the boot? (see, I really am that dense!) LOL

[dilbert]

I suppose one could always drill a 500 thou hole if the problem got really bad!

What does one do if water collects in the headlamps?

[tvrbob]

dilbert said:

What does one do if water collects in the headlamps?

The headlamp glass should have a drain hole at the bottom. It's a small area that doesn't have any sealant. If yours is collecting water then perhaps the glass has been refitted and sealed all the way round.

[dilbert]

I'll see if I can find a carbide bit then!

[tvrbob]

dilbert said:

I'll see if I can find a carbide bit then!

No don't drill the glass.

At the bottom of the housing there's a trench. This forms a gap under the glass. I'm suggesting that someone may have inadvertently put sealant there.

[dilbert]

[chimleic]

I'd still like to see a pic before I take a drill to the back of my car. Anyone please?