I have been dealing with water pooling in my spare tire well in my trunk after rainstorms. Today I pulled out all of the panels, jumped in there, and had my wife soak the outside with a hose. I found water coming in through the hole for the LED connection plug on the passenger side rear tail light.

Seemed to be more noticeable after she stopped spraying and I opened the trunk. I'm not sure if that was because of water running off of the open trunk, or just because it got bumped. There was quite a little pool of water in the light assembly behind where I was pointing. In the attached picture I'm pointing to the plug where the water appears to be coming in from.

What I can't figure out is if there is a problem with the light assembly itself, the gasket, or perhaps the trunk seal. The gasket doesn't really seem to be a seal at all - it is a spongy material that doesn't seem like it's designed to keep water out anyways.

I included a picture of the trunk seal, I'm not sure if it is supposed to interface with the lens assemble in the way it does by lapping over it at the top (circled in the pic). Both sides are like that.

Any ideas on what I should look at next would be much appreciated! Not sure how the water is actually getting back there. Thank you!

 

Water should drain on the right side of that seal in your second picture. That spongy material behind the headlight is a seal. This seal going bad was a common problem on Accords in the 90s where water would get into the rear taillight.

I'd suggest replacing that spongy seal. Inspect the plastic taillight for obvious crack when you remove it.

Has you car ever been damaged in that area?

 

I recommend if you can fold down the rear seat, do so. Take a garden hose and put it on top of the car, get inside with a flash light and narrow down or find where the water is coming from. Good luck!

 

Thanks for the responses. I ordered two new tail light gaskets - I figure if one is bad the other can't be far behind, and I'd rather just do both and be done with it. They should get here by the weekend when I'll have time to install them. Hopefully that will solve the problem. I'll follow up with a post after I re-test with the hose.

And the car hasn't sustained body damage in the 55k that I've owned it, but the bumper cover is not original so it has definitely had some sort of issue at some point....

 

Hard to call, in the second pic part of the trunk seal looks to be pulled up where the "gray" part is.....compare that to the other side and address if needed. I don't think that "pulled up" part is the issue but you are there, might as well take care of it if need be.

 

This afternoon I replaced both tail light seals. I then gave the outside of the trunk a severe flooding with the hose, and the inside of the trunk stayed bone dry! I'm going to keep an eye on it for a bit, but for now I think the tail light seals may have been the culprit. Thank you all for the help.