Water leaking into cab when rains - passenger side only

[2Kchevy]

Hello.

I have a 2000 RCSB silverado 1500. Pics of the issue attached below. The 2 pics of the kick panel are rotated 90 degrees, so you have to turn your head...they are oriented properly in my picasa viewer but that is how they uploaded on here.

I have noticed water leaking into my cab after a huge rain like we have recently experienced in Texas. Water also leaks when I wash my truck. It is not coming from the evaporator or heater core as it only leaks while sitting during rain storms and washing.

I removed the interior panels from the back glass to the lower kick panel and did some tests with a water hose.

I noticed water leaking from around the cabin air vents in the rear, the speaker wire grommet going into the kick panel/body, and where the door is welded or attached to the kick panel/body.

I replaced the cabin vents and placed electricians putty around the edge and this fixed the leaks around the vents.

Electricians putty did not work well for the speaker wire grommet, so I now used black RTV around the grommet and around the door mounts on the kick panel/body as much as I could reach w/o removing the door (i.e. 3/4 of the mount, could not get the edge facing the engine).

Well, we just had another rain storm this past week and once again there is still water leaking on the passenger side only. It fills up the passenger side kick panel and then flows down to the passenger side floor. I keep the interior panels off on the passenger side so I can soak up the water after a storm.

Before I proceed with removing the front fender to see how else water can leak into the passenger side kick panel, I figured I would post on here for more ideas.

Any thoughts on how/where the water is getting into the passenger side kick panel?

Thanks.

Pics:
IMG_0378.jpg
IMG_0395.jpg
IMG_0393.jpg

[bartjo06]

I bet it's the third brake light, they're notorious for leaking on NBS trucks and will leak down the b pillar and pool on either side. Check it out.

Also, check the grommet where the speaker wiring runs from the cab to the door.

[Crazy Blu]

My 02 gmc door seals leaked in touchless carwashes

[1BadCC]

Check around the windshield for leaks. We reseal 2 or 3 a week from the urthane breaking loose or deterorating

[vrod25]

I had the same issue with my 08 rcsb, I replaced the third brake light and inspected the old lights seal, it was flat and falling apart. Havnt had any water back in the cab

[RS/SS 4.8]

I had the same issue with my 08 rcsb, I replaced the third brake light and inspected the old lights seal, it was flat and falling apart. Havnt had any water back in the cab

X2 i had the same problem on my 07 nnbs.

[RedHeartbeat]

you guys are lucky, my whole back glass is about to fall out.

[RS/SS 4.8]

Thats no bueno

[Ray@NP]

we used to reseal windshields for the urathane not sealing properly and like the other guys said the third brake light also leaks. make sure that your weatherstrip is sealing good against the door or you can adjust the stricker to pull the door in a little more