dave, the usual suspect for a leak on the passenger side of the cab is the wiper cowl, the black piece of vented looking plastic that goes under the wiper arms across the windshield base. anyhow, the wiper cowl is in 3 sections. there's a center section with 2 or 3 screws, and then the 2 ends have a tongue that tabs into the center section and screws into the top of the fender. anyhow, a couple of those screws ********* into the cab above the blower motor. i suppose that once upon a time there was either a sealant bead under these screws, or maybe the metal was tight enough around the screw threads that it didn't leak. anyhow, over time, either light corrosion or sealant failure happens, and rain/melted snow/etc. will follow the screw through the hole and drip inside the floorboard on the passenger side. mine was leaking there too. i put a spot of windshield urethane sealant (3m) and covered the bead up with a piece of sound deadening stuff, you could probably just let it ride without the sound deadening stuff, just figured it would help, or couldn't hurt at least, and i was in the middle of sound deadening my truck. probably unnecessary, but i had it at my disposal. i'm rambling, i'm sorry. there was a second leak on mine, on the driver side. so, let me see if i can explain exactly where this is... if you open your hood, look on top of the firewall, at either side of the truck, just inside of the fender, on the horizontal portion of the firewall area. there is a good deal of factory sealant there on that flat portion where the vertical part of the firewall comes up and seams up with the horizontal portion. (probably considered more "cowl" than upper horizontal firewall, but you hopefully see what i mean.) anyhow, my sealant there had failed and it was letting water in on the driver side floorboard of my truck. got some windshield adhesive -- the urethane stuff (3m i think) and prepped it with some brake parts cleaner to clean it up good, and spread it on there with a putty knife on both sides (driver/passenger) and then sprayed it white to match my truck with some rattle can paint. don't use regular caulk. they can cause further rusting because of the chemicals given off from curing. i know it's kind of a mixed up read here, but i kept going back and forth thinking of other stuff while i typed it, just not too excited about it to go back and retype it. hope it works out for you man. branndon