I have the seat and carpet out of my truck down to a clean and painted floor, and it rained good today so I went out and looked for leaks. I found water coming in from the corners of the sliding rear window and some water trickling down the inside of the firewall near the fuse block and the other side near the heater and a little more in the center running down near the trans hump. I have new seals ordered for the front windshield and the rear slider along with a new windshield hoping this will stop the leaks. Could it be leaking from somewhere else ?
Thanks , Gene

 

There is a drain opening for the cowl that is about the back of the fender. You may find it with the door open. Mine was clogged with leaves and I cleaned it out with a clothes hanger. This is for the right side, left is probably similar.

 

The windshield wiper stub gaskets leak. fuse box and at back of heater