Hey y'all, once again i tried searching and could not find anything helpful for me. The problem is with my 94 GMC, when it rains, or even a few days after it rains, the passenger side floor becomes wet. I have checked underneath, and can find no spot where water could be getting in.

Someone mentioned that it could be coming through the firewall...? Any help would be great, thanks!

 

I would pull the carpet back and have someone spray the truck with a garden hose while you are inside looking for the intrusion spot. I had a windshield leaking once and it was letting water run down the pillar and soaking the carpet. I had to have the windshield resealed.

 

Hey Max it is more then likely your windshield seal. Gm has designed the pillars in thier truck to route the water there if they do spring a leak. It may seem stupid but it is to prevent water from laying in the bottom tray where your windshield sits. Thus preventing unseen and unnoticed rust from happening. The best way to find out is to use a garden hose when the carpet is dry and start running water all around the windshield seal at the top. run a good amount of water all around the windshield and then check your carpet.

Now if this does turn out to be your problem there are two ways to fix it. You can just call a windshield company and have them come out and reseal your shield, or I have seen people just run a very tight bead of silicone around the seal on the outside. I would recommend having it resealed but if your just looking for the quick cheap way out the silicone can work. Retest it after to be sure you got the right spot.

 

Thanks for the tips so far, hopefully I can try them out this coming weekend. I have noticed an area of rust underneath the general area that is wet, rest of the underbody is pretty clean. Guess i'll find out soon enough.

 

Pour some colored fluid where you think it might be leaking to trace the leak. Just a thought.

 

If the leak is your windshield, you can use silicone to fix it.

 

I have the same problem on my '94 Silverado K1500 extended cab. After extended or heavy rains, I usually notice some water on the passenger side floor mat. It doesn't wet the carpet though, the water usually rolls off the floor mat and then out through the bottom of the door. I've always thought that it's coming from somewhere under dash or hood. I don't think it's coming through the windshield.

I also get water in my air conditioning system (or maybe just the ducts) after extended or heavy rains. I can hear the water when I turn the A/C on the low position. Then I set it to the highest position to blow the water out. I don't know where the water goes but it doesn't come out through the A/C vents on the dash when I blow it out