I have a 99 Ford F250 Super duty extended cab and recently noticed a lot of water in the passengers door floor sill under the sill plate. The carpet was pretty wet. The leak is definitely not coming from the front of the truck...we can tell that. It appears it's coming from somewhere in the back and it's the passengers side only. The sliding rear window looks o.k....but no obvious signs of a leak...same with the third taillight. Any thoughts?

 

Did you ever find the source? Was it front or rear passenger? My front passenger leaks water from the engine compartment though it somes in from the rain somewhere around a seal.

 

I had a big leak on mine it was the vent in between the cab and bed. Pull the trim back get a hose and see if thats your problem...



Dick