I need some help with my 97 b4000 extended cab. I recently picked it up and discovered it had a leak when it rains. The water pools on the passenger side that wraps around from the footwell alongside the door to just behind the passenger seat.

I thought maybe it was the windshield seal and luck had it, I needed to replace the cracked windshield anyways… However this seems to not be the cause of the leak as it’s still happening even after having taken it into a shop to get a new windshield.

I have taken the fender off and cleaned out the windshield drain thinking that would do it after seeing advice on that, but it still leaks.

I do not think it is the heater core as my coolant has never dropped over the several months I’ve had it, and I’ve even flushed the heater core and seen no leaks.

The most recent thing I have done is taken all the trim off in the footwell pulled up some of the carpet and had someone pour water over all the seals (both windshield and door) to see if there were any noticeable leaks, and still nothing.

Ive read that it could be leaking from the third brake light on the back of the cab, but I just don’t know how a leak would get from there, avoiding most of the floor in the back, and pooling in the passenger footwell.

Does anyone know if it could be leaking from the third brake light causing the passenger foot well to be soaked overnight?

 

It may be coming in from the vent plenum that is between the windshield and the hood or the seal around the wiper arm stud