Third brake light gasket is common. Search for it to find how common it is and how to repair it.

 

CHMSL (Brake light above the rear window)
Sliding rear window (if applicable)
Windshield
Cowl (hinge area)
Firewall (wiring grommets)
Roof weld joints (under the black plastic molding)

With someone in the truck, get a water hose and start hosing down the outside with some pressure. A DIY car wash is a good place to do it. You may have to remove more of the interior to pinpoint the leak.

 

I had water come in on the drivers kick panel when the drains were plugged with leaves and misc. other debris also. Can't hurt to cover all the bases.

 

I thought about that the first time I had the carpet out. Both left and right kick panel areas were bone dry. I took off the cowl and poured water over the entire front end. Drains were clear and no indication of a leak from the front end. All the plugs were dry as well. So I have a feeling it is either the the break light, window or the channel on the roof. I will need to pull the truck completely down to find out. And since I need to pull the wet carpet out yet again, pulling the rest of the interior won't be an issue. It's raining out now, but I can't see any signs of leaking with the interior in.

 

I ended up using 100% silicone to gasket my 3rd brake light when my seal finally failed. Eventually I'll replace it with LED's and get a real gasket there.

 

LED replacement break light, now that's an idea I didn't think about.

 

You guys need to come up with better suggestions. He's read all those forums - he said he's been looking and hasn't found the same problem he's experiencing. LOL

 

My mystery leak was the 3rd brake light. Don't use Silicone though, it won't last. Get some butyl tape that is made for glass sealing, they sell it at most auto parts stores and home depot type stores. It will last longer. You won't need to tear it down either, pour water back there and you will probably see it disappear.

 

I pulled the third break light out today. It seems to be the issue. It looks as if the sealing tape was pushed down where each of the lights are at. Like four rain gutters. Also have standing water inside the light housing. It's wet along the channel as well so that's my issue for sure. Thanks guys. Will be fixing it as soon as I can.

 

What a piss poor design

 

Well, I made a new gasket for my third break light. Hope that ends my leak as it seams to ne where it was coming from. Pulled my carpet out again and replaced my deteriorated pcv molded pipe. Next on the to do list, breaks, shocks and find out what seems to be loose in the front as it makes noise over bumps and can feel it in the floor.

 

I'm not sure if I can understand what you wrote.

Did you say to put Vaseline on it, let it dry then wipe it away? What does this accomplish?

 

I read as you use the Vaseline so the light and seal surface create a mold, creating a removable silicone seal that isn't bound to the light. Then you can remove the light fixture without compromising the seal?

Clarification would be good. First I heard of that one.

 

Yes, vaseline will prevent the silicone from adhering to either surface. The loose fit of the install of the light forms a consistent seal. After drying, clean off the vaseline and install your new seal.

 

‘12 Crew Cab water leak

Discovered that the carpet in the corner (driver’s side) behind back seat of my ‘12 crew cab is wet and with lots of rain it runs down to floor by rear door. Just noticed it after last rain. Headliner shows no water . Can the 3rd brake light be the issue even though the headliner is totally dry? Any thoughts on the cab vent in that corner or seatbelt bolt? As you all know the access to see much back there is really limited without pulling out the seat and plastic cover against the back of the bed. 3rd brake light is easy to work with but without wet headliner is that still possible cause?