Putting supplies in the cargo area this evening and I noticed a cup worth of water inside the drivers side upper tail light housing. Is this normal or is one of my tail light seals shot? And could this eventually damage the electrical/bulbs?

 

Yes on the damage to bulbs and sockets. Mine does not have water in them, plenty of recent rain. Don't know if seals are good or drains are good.

 

Usually if you look real close you can see cracks in the surface of the plastic, it gets oxidized and hardened by the sun and starts to crack. Yes, water will affect your lights, if you don't want to spend the money to buy new ones, you could take the assembly out and drill a small drain hole in the bottom so the water could run out, then put the assembly back into the body.

 

I did not notice any cracks, but I'll take a closer look and see what I find. Thanks for the tip, I'll consider the drain hole method for now Luckily the bulbs are still working though...

 

I had the exact same issue and I ended up drilling a very small hole at the bottom of the light (make sure you unmount it and do this on the inside, unless you dont mind a hole on your light!), and it worked just fine for draining, but a few months after that I notice excessive fogginess in the light, so I ended up getting a new housing after inspecting the light and realizing that the whole light had a crack through it.

 

Drill baby Drill... all will be fine.

 

If no cracks, it's possible that the last person that replaced a bulb didn't securely attach the back portion to the assembly. My 03 has some cracks, and it gets water in it, but it never fills up... usually just some droplets you can see on the lens.

 

If no cracks then take it out and really investigate if it can be fixed without adding a hole that's the best route. Making a unnecessary hole is a invitation for moisture if its a crack on inside or seal you should be able to seal it up.


If you can not see a crack you can run water over it and look for where it is making its way in threw the lens.

 

Drill three holes, two on the bottom, one on each side of the lens, one in the highest spot of the lens.
This allows the water to drain out and cross ventilation to prevent the lens from fogging over.
Use the smallest drill bit you can, they dont need to be big holes.
I did this to a Ford van, the corner lens filled with water, which is common on the Econoline vans.

 

I had to do this on a Jeep. Works great.