Water Pooling Under Rear Bench Seat, Can't Find The Leak

[Art Vandelay]

I've seen a lot of posts about water leaking into the interior on the front passenger side floor, the rear passenger floor, the firewall and the headliner. But I can't find any posts here, the FB group, the Reddit group or a Google search with the issue I just found on my Lariat Hybrid.

I've been telling my wife for months that the inside of the truck smells funny, like mildew, but I can never seem to find water. Well we just had two days of heavy rain that ended last night. I hadn't used the truck at all today until just about an hour ago and when I got in I noticed all the windows were completely fogged on the inside and it was like sauna in there. So I went searching again with a flashlight for all the usual spots and didn't find anything wet.

Then I lifted up the rear seat bench for the heck of it and sure enough there is water in the under seat cargo area. The top of the cover for the 12V battery was wet and you can see water pooled in the indents circled in yellow in the picture below. There did not seem to be water where I had things stored in the cargo section under the seat but it was fairly hot outside to today so I'm thinking a lot of it evaporated and that's why the windows were so fogged.

A few things:

The head liner was not wet at all and there are no stains on it so I don't think it's the sunroof or third brake light.

There seems to be a lot of debris scattered like pieces of dirt and leaves which would lead to believe it's carrying dirt in as well.

Also I tried using the garden hose to rear sliding window, the moonroof, and the rear window but didn't see any water coming in. It's also dark outside and I was by myself so I will try again in the morning when it's daylight and someone else is home to hold the hose while I watch the inside.

Any ideas?

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[gjallen3]

Check the Cargo light/ 3rd Brake Light seal

 

[Cancunbadlands]

Third break light, rear sliding window?

 

[Art Vandelay]

Third break light, rear sliding window?

I tried holding the garden hose right above the rear sliding window and didn't see anything coming in. However I was trying to do it while standing out side the truck holding hose but putting my head inside and it was dark. I'll try again tomorrow in the daylight and I'll have someone assist so I can be inside the truck.

 

[Art Vandelay]

Third break light, rear sliding window?

I did hold the garden hose on the roof and let water trickle down and didn't see anything but it was dark outside and I was by myself. I'm hoping to have better luck tomorrow morning in the daylight when someone else will be home to help me.

 

[gjallen3]

I know you checked the 3rd brake light already but you might just want to check it again. I had a leak there and it didn’t stain my headliner at all. The underside is somewhat water resistant. The seal on the brake light is not very pliable and has room for improvement. You may also want to check the antenna.

 

[Oldschool_Chief]

Im going to seal my 3rd brake light with silicone as a preventative.

 

[Louie1]

I've seen a lot of posts about water leaking into the interior on the front passenger side floor, the rear passenger floor, the firewall and the headliner. But I can't find any posts here, the FB group, the Reddit group or a Google search with the issue I just found on my Lariat Hybrid.

I've been telling my wife for months that the inside of the truck smells funny, like mildew, but I can never seem to find water. Well we just had two days of heavy rain that ended last night. I hadn't used the truck at all today until just about an hour ago and when I got in I noticed all the windows were completely fogged on the inside and it was like sauna in there. So I went searching again with a flashlight for all the usual spots and didn't find anything wet.

Then I lifted up the rear seat bench for the heck of it and sure enough there is water in the under seat cargo area. The top of the cover for the 12V battery was wet and you can see water pooled in the indents circled in yellow in the picture below. There did not seem to be water where I had things stored in the cargo section under the seat but it was fairly hot outside to today so I'm thinking a lot of it evaporated and that's why the windows were so fogged.

A few things:

The head liner was not wet at all and there are no stains on it so I don't think it's the sunroof or third brake light.

There seems to be a lot of debris scattered like pieces of dirt and leaves which would lead to believe it's carrying dirt in as well.

Also I tried using the garden hose to rear sliding window, the moonroof, and the rear window but didn't see any water coming in. It's also dark outside and I was by myself so I will try again in the morning when it's daylight and someone else is home to hold the hose while I watch the inside.

Any ideas?

My Gord Sport Trac use to do that Somet. It’s the light above the rear window not the window. It will come in and drip down from the trim. I purchased the rear cab spoiler to try to protect the light from the hard rains.

 

[ListedGuru]

Im going to seal my 3rd brake light with silicone as a preventative.

Please post back and let us knows how that goes and what silicone you end up using. I've thinking this might be a good idea just in case....

 

[Oldschool_Chief]

Will do. Probably going to use a black maybe high temp?

 

[Louie1]

Please post back and let us knows how that goes and what silicone you end up using. I've thinking this might be a good idea just in case....

 

[Louie1]

Sealant did not work for me. I had to have the third light unit replaced.

 

[Msradke]

When I was working on the audio upgrades on mine I noted a slight water leak in a body seam behind the C pillar trim left side

 

[icegradner]

I had my high mount brake light replaced due to water issues, it’s very likely to be the problem.

 

[Art Vandelay]

I just went out side and had I had my daughter hold the hose first over the sunroof, then antenna, then third brake light and finally above the rear sliding window. I was in the truck with a flashlight and not a drop got inside We were out there trying different spots for almost 30 minutes. I thought for sure I'd find the source today.

Now I'm debating if I should just bring it to the dealership to see if they can find the leak or just wait and keep trying.

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