Fixing Tail light lens moisture

[hamiltonmj]

I was trying to figure why I was getting moisture in my left side rear tailight lens. I unscrewed both the rectangular lenses ( I have a 2008 IOB) (they are plastic) and there was an inch or two of water in the taillight housing. I examined the the plastic taillight housing and noticed that the factory installer had overtightened the screw holding the lens to the tailight housing and broke the plastic "surround" that tightens the lens to the housing. Although the screw looked like it was holding the plastic housing in, it was only for show and allowing moisture to seep into the taillight housing. I put a washer in the screw and tightened it again, this time tightening the lens to the housing and preventing moisture intrusion....

[Ray Eklund]

This is among a list of exterior lights that get moisture on the rear of our 2006 Safari.

The tail lights have rubber gaskets which do not seal out moisture nor dust. The plastic decorative outside chrome like trim split at the screw holes or the holes enlarge from vibration and I add a washer when I screw the split or enlarged holes to the aluminum tail light. I could not get a parts quote for replacements from Jackson Center, OH, so just cobb them to hang on...

I took a drill and drilled two holes at the base of the aluminum tail light to drain any water that might collect in the tail light interior. It has worked for me. You can see where the low spots are in the tail light housing and you can drill one, I drilled a 1/8 inch drill, or two. The first time I took them apart there was enough water in each to fill a couple of "shot glasses".

The plate light always needs to be cleaned as it is not an enclosed fixture. The plastic is always coated with dust when you travel off asphalt. I have one or more rear trim lights will get moisture and those... are sealed. I do not check them for moisture since our drought, but as long as they are working I had better not be pulling them off to create more trouble later with them staying tight onto the aluminum shell.

At least we get NO WATER inside the trailer.

[hamiltonmj]

Thanks. Drilling holes is my next option but it doesn't happen on the right side. I'll check it tomorrow for leaks.

[Protagonist]

When replacing screws in an exterior light fixture, it's important to make sure that:
1 - None of the screws are loose;
2 - None of the screws are too tight;
3 - All the screws are tightened to the same tension.

Overtightening can cause the gasket to leak in between the screws. If you compress the rubber too much at the screws, it bulges out the sides and still messes up the seal.

Undertightening can cause them to leak at the screws.

It's like Goldilocks; in-between is just right.

Also note, incandescent lights can get very hot if they're left on for a long time. If the plastic lens feels hot to the touch after the light has been on for a while, the plastic could be warping just enough to cause a leak. The plastic wouldn't warp much, and would probably return to its original shape after it cools down. This effect is most noticeable on boat trailers, when a hot taillight gets submerged and cools off quickly; even though the light fixture is supposedly waterproof, it would still come out of the water with water trapped inside. On a travel trailer, the effect is more subtle.

[hamiltonmj]

Checked them and there was no water in the tail light housing. Make sure the tail light screws are tight but not too tight which breaks the plastic screw housing and keeps the rubber gasket from sealing the lights.