Rear light (FL-style) condensation

Enjay · August 2, 2018, 15:35

Anyone able to help out here? My rear lights keep getting condensation in them.

I have had them off the car, dried them out thoroughly, resealed them with some heat-gun action, butyle beading and quite a bit of time and effort and... no improvement. (:< >

My car has FL rear lights (despite being a PFL car) and I noticed that I can just, ever so slightly, catch the edge of the colourless round lenses with my fingernail. Obviously, these are a separate moulding to the red-coloured parts and it's also those areas that seem to get the condensation (all 4 of them). So I wondered, is it possible that there is a tiny gap between the colourless and red plastic - just enough for water to seep through?

I have been toying with getting my rear lights "smoked". I think that is done by applying a vinyl-like film over them. If that's the case, then presumably that would seal the lights if there is a gap between the plastics - or, if I don't go the smoking route, perhaps just a completely transparent screen of some sort?

BahnStormer · August 3, 2018, 08:36

Quote from: Enjay on August 2, 2018, 15:35
Anyone able to help out here? My rear lights keep getting condensation in them.

I have had them off the car, dried them out thoroughly, resealed them with some heat-gun action, butyle beading and quite a bit of time and effort and... no improvement. (:< >

My car has FL rear lights (despite being a PFL car) and I noticed that I can just, ever so slightly, catch the edge of the colourless round lenses with my fingernail. Obviously, these are a separate moulding to the red-coloured parts and it's also those areas that seem to get the condensation (all 4 of them). So I wondered, is it possible that there is a tiny gap between the colourless and red plastic - just enough for water to seep through?

I have been toying with getting my rear lights "smoked". I think that is done by applying a vinyl-like film over them. If that's the case, then presumably that would seal the lights if there is a gap between the plastics - or, if I don't go the smoking route, perhaps just a completely transparent screen of some sort?

Sorry, no advice on this, other than I was concerned when I first saw mine, but I was told "it happens to them all, just about nothing that can be done about it".... following this thread with interest though

Enjay · August 3, 2018, 21:11

Quote from: BahnStormer on August 3, 2018, 08:36
Sorry, no advice on this, other than I was concerned when I first saw mine, but I was told "it happens to them all, just about nothing that can be done about it".... following this thread with interest though

I had a 64-plate (FL) Nissan Juke for a while and the rear lights got full of condensation within days of me getting it home. I called the dealer and that's pretty much what they said about that car too. $:-\$

Topdownman · August 3, 2018, 21:45

No idea how the water gets in but the traditional advice is to drill a couple of holes in the bottom of each of the two clear lens tubes to allow what gets in there to evaporate by air movement when you are driving.

Thats what I did and it definitely helps clear mine but doesnt solve it happening.

Gaz mr-s · August 3, 2018, 23:33

Quote from: Topdownman on August 3, 2018, 21:45
No idea how the water gets in but the traditional advice is to drill a couple of holes in the bottom of each of the two clear lens tubes to allow what gets in there to evaporate by air movement when you are driving.

Thats what I did and it definitely helps clear mine but doesnt solve it happening.

I didn't know about this mod, but wondered if something like that could be done. What about having a small tube extended to try to feed air in?

delhusband · August 4, 2018, 10:09

Happens to mine. Dont fancy drilling. Or trying oven trick to get lens off and reseal. I take it theres no chance it could be improved by trying something like placing any additional rubber/sealant between the bulb entry hole and the bulb? Ive always meant to have a look at this, never got round to it

Topdownman · August 4, 2018, 11:51

Just heard another tip at Shin ding day and that is to remove the plastic cap on the back of the light.

Call the midlife is trying it out and no doubt let us know if it works!

Call the midlife! · August 4, 2018, 19:52

Just for you, that's after 2 hours up the road home! I'll let you explain it, I'm still 90 minutes from home [emoji23]

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delhusband · August 4, 2018, 20:15

Take it that's essentially given it some extra ventilation whilst driving then - they look nice and dry

Topdownman · August 4, 2018, 20:37

Yep, that was properly wet in there before he set off, even in this heat.

The tip came from Dean at rutlandmr2 apparently.

The cap is about 1cm across near the top of the light, the guy who told us (sorry, forgot your name already!) just popped his hand in by feel and a few seconds later it was off.

I guess the mod is easily reversible too if there turned out to be a problem?

Call the midlife! · August 4, 2018, 21:27

I can't reverse it on the offside lights as there were no caps on them when I got them.[emoji23]
And no condensation either.

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Gaz mr-s · August 5, 2018, 10:12

Quote from: Call the midlife! on August 4, 2018, 21:27
I can't reverse it on the offside lights as there were no caps on them when I got them.[emoji23]
And no condensation either.

So was your light with the cap on the only one that got condensation.... the cap-less didn't?

Gaz mr-s · August 5, 2018, 10:21

I have a set of FL lights waiting to go on a PFL, so had a look. 20mm diameter white-ish nylon, it is. It is not easy to get fingers onto, - I had to use a screwdriver to prise it off.

It has foam at the top of it to make a nice 'airtight' seal.

So if removing it does the trick we want.... wtf did 'Toyota' fit it for? Further down in the recess there is what looks like a white plastic tube around 5mm diameter.

Addendum....it's not really a tube, it bends at a sharp angle a few mm down. I used an 8" long piece of tennis string & the whole length can be pushed down, - not visible looking from the outside face of the light. So maybe it's for general venting in the back of the light??

Call the midlife! · August 5, 2018, 10:27

That's the one! And no, the dry one had no caps on it when I got it, they're reclaimed units from Dean so not necessarily a matched pair either.

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Call the midlife! · August 14, 2018, 22:25

Still dry as a bone even after a couple of washes and being stood in the garage for a few days.

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deviantmr-s · August 15, 2018, 12:07

I checked and I had one plastic cap at the top of one light and one at the bottom of the other, two areas where caps cover.

Both mine suffer from condensation - so removed both of these plastic caps (petite hands so no problem removing either).

Unsure if this has worked as not checked since I did this!

Will check and get back to you, as my lights suffered really badly and I am keen to see if this works.

Enjay · December 2, 2018, 17:43

Arise my thread:

I decided to get some subtle tints put on my rear lights (basically just a tinted vinyl film as far as I can tell) and it does seem to have improved the condensation situation - but it's not cured. I hadn't noticed all the comments about the caps but I planned on taking the lights out and keeping them inside over the winter, once I eventually tuck the car away for the worst couple of months (still using it ATM). So, I'll give the housings a good look over and see what can be done. The caps thing does seem to be making a difference for other people so that might well be a good way forward.

deviantmr-s · December 2, 2018, 18:07

Removing all caps has made no difference to the condensation for me at all.

Another member I know of has drilled a small hole to allow a small airflow from the front sealed housing into the area that the caps give access to.

Thanks for resurrecting, as I forgot to chase it up.

I look forward to hearing how you get on and find.

benjamino · January 5, 2019, 18:56

I took mine apart, cleaned and put back together. Condensation was back the next day!

Take two. This time I've a silica bag in each one, with a thin string attached so I can pull them out to replace when they become saturated. Just poked it through one of the bulb holes. The bulb goes back in with the string still hanging out a bit.

Condensation totally gone within 3 days. You can just see the bags if you per closely but not unless you're really looking. Time will tell how long the bags last but I'm hoping for 6 months! Swapping them is a small price to pay for clear lenses.

Gaz mr-s · January 5, 2019, 21:27

I believe the moisture is condensation, rather than water ingress. I worked on doing a mod to a light approx September last year. I have a PFL & want to use the FL lights....but having had a FL car this issue pees me off, as it does to others.

I fitted ONE spare modified light to a FL car. Over the period of a week with mixed weather & the car UNUSED...both rear lights remained clear. It was only after the car was used that the condensation occurred. BOTH lamps got it, but the one I modded cleared, the standard one did not, - this is with the plastic plugs removed....I noted no difference with them fitted or removed.

So that's why I think it's caused by the engine bay getting hot & the condensation occurring.

Unfortunately I lost access to the car mentioned in October, so the idea is on hold for now. When I get them on my car & test the mod I'll post about it.

Enjay · July 11, 2019, 18:57

I just wanted to resurrect this thread (once again) to give a further update. My car was outside for a lot of the winter and in some pretty wet weather. The rear lamps have not shown any obvious condensation. Perhaps my earlier assessment of the condensation being better but not cured was because there was still a little dampness inside the lights when I got the tints put on.

Either way, my rear lamps have not had any obvious condensation in them for months now. So, it seems as if my hunch about water maybe getting in through the join between the red and colourless plastics might have been correct.

Brackers · May 11, 2020, 21:46

The rear lights consist of the black main housing, a rubber gasket and the lens.

Typically the gasket fails. To replace it you need to remove the entire unit and then pry off the lens. Best to heat it up with a hair dryer or put the unit in the oven at lowest temp. Save the side with the 3 tabs until last, though even then they often break in my experience. Toyota still sell the rubber gaskets for a couple of quid, and the outer lens, should you break the tabs for £80 approx.