96-2500 leaking like a siv
 

All of a sudden my truck has water pooling on the floor infront of and beneath the front seats. It only happens when it rains, doesnt matter how hard and the truck is just sitting. I cant find any drips or visible trickles of water.
HELP!
Dont want my floorboards to rust out.

Have checked the door and windshield drains? It is a 96 and dirt,rust and even factory labels could be blocking the drains causing backup into the cab:peel::D:D

Check the rear window and the 3rd brake light.
if thats not it, try lifting the carpet and look for rot where the firewall slopes down to the floor.

Usually the third brake light gasket is dry and cracked.

If it doesn't smell like anti freeze its probaly not ht heater core, however the A/C condenser drain tube can get blocked and back up into the passenger floor. Its on the fire wall under the hood lower right side.

my drivers side is a swamp too, like standing water on top of the carpet! Where should I look for seals and drains? The headliner is wet just above the drivers seat next to the drivers window, but the seat and door is dry. can it still be the 3rd brakelight seal?

A wet headliner sounds like a poor seal between the door and cab, or a bad window seal.

The third brake light gasket is the first place to look on the passenger side, then the a/c drain. For the drivers side i'd guess door/window seals. Or a window left open in a downpour.

Yep 3rd brake light seal will get ya every time ;)

I will make a quick video of the leaks and destroyed headlinter sunday, its terrable and has been leaking well before i bought it- rust on the metal seat supports and mold on the seatbelts. no fun in a area that gets 100" of rain a year.

Ditto on that sneaky 3rd brake light. I pulled mine and used 3M body putty--the stuff that comes in ropes--to reseal it. Hasn't leaked since.

Video
http://youtu.be/BZWesRkK3-I

Easy way to pinpoint leaks is to tape over the exhaust vents located on the lower rear door frame.
Turn the fan on high to pressurize the cab.
Spray soapy water on the suspect areas, bubbles will lead you to the leak.

My truck leaked water on the passenger side floorboard when parked facing down hill and the cause was a tear in the plastic sheet behind the door panel (AKA Water Dam in the parts manual). Once I replaced the water dam my cab has remained dry.

First dry day in months, here is the rear brakelight- not much of a seal left.

Attachment 59771