'08 Sierra Wet Behind Driver Seat

[shurguywutt]

So I have been tracking down wet floorboards in my Sierra and I am at a point where the next step is taking the seats/carpets out (hoping to avoid).

This is what I've done so far:

1. Replace rear high brake light & seal.
2. Seal both weather strip grommets with silicone (above cab on left and right side).
3. Replaced both cab pressure vents.
4. Check weather stripping on doors and roof with hose. No moisture evident inside after.
5. Confirmed all sections of the floor are dry other than under the carpet BEHIND the driver's seat.

This is the strangest thing because it is almost like water is coming up through the floor under the seat. All areas around this wet spot appear to be dry.
My next step was to remove the seats and carpet and see if I can find where the leak is with baby powder. I Don't understand how else its getting wet if everything around it is still dry.

Its an extended cab.

Thanks for any help.

 

[RooflessVW]

The door membranes failed on my X3 and water would drip from the bottom of the interior door panel onto the sills and down to the rear foot wells.

 

[TCL]

Rot at the back of the cab corner or seam? Pull up the carpet.

 

[ekrampitzjr]

Rot at the back of the cab corner or seam? Pull up the carpet.

This. I see entirely too many recent pickups with rear cab corners rusted away. All three of the Big Three are guilty. The older pickups had their problems, but most didn't do that.

 

[shurguywutt]

This. I see entirely too many recent pickups with rear cab corners rusted away. All three of the Big Three are guilty. The older pickups had their problems, but most didn't do that.

Interesting. I didn't see any damage on the underside and there is very little rust overall. Good thing women don't ride in my truck... I guess the carpets are coming out. Any advice on the best way to repair?

 

[64bawagon]

We had a number of 09 Tahoes at work that had all been repainted. When the door seals were removed they were damaged by carelessness, reinstalled and not replaced. Every one of them had water intrusion down the A pillar and into the wiring trench under the sill plate.
The plate is easy to pull and will either have water in it or witness marks from water if they are leaking.

 

[shurguywutt]

We had a number of 09 Tahoes at work that had all been repainted. When the door seals were removed they were damaged by carelessness, reinstalled and not replaced. Every one of them had water intrusion down the A pillar and into the wiring trench under the sill plate.
The plate is easy to pull and will either have water in it or witness marks from water if they are leaking.

Right. This is an 08 Sierra with extended cab. No pillars. I have the plates pulled and the carpets lifted (been riding like this for weeks) monitoring the moisture levels. A part of me thinks the moisture is just residual after I have made my repairs. I also have a damp rid bucket in there absorbing anything in the air.

There was evidence of water in the plates but they have been dry for a few weeks.

But yeah I totally get the poor workmanship. Nobody takes pride in their work anymore. It's sad.

 

[01rangerxl]

Granted it's a different application, but on the Rangers I've had, when it wasn't the brake light, it was the windshield. If the truck has been wrecked, that's definitely suspect.

 

[64bawagon]

The A pillar is the one that the front door hinges are on.

 

[shurguywutt]

The A pillar is the one that the front door hinges are on.

Gotcha but the moisture is in the rear.