I have a 1995 ram 1500. The driver side floor gets wet every time it rains. I have replaced all door seals, side window wipers on both drivers and passenger side windows, replaced windshield and new gasket on 3rd light on rear of cab. Nothing has stopped the rain from getting into the drivers side. Any other ideas where it's coming from?

 

Lay on your back on the front seat, have someone else hose the truck down, see if you can see where the water is coming from.

 

Is the cowl rusted? Check behind the front wheel area between the hinge and cowl. Do what Hey You said, If it's rusted you will see rust stains coming from where it is getting in.

 

Get some cheap baby/talc powder. Put it on the vertical surfaces. It will leave a snail trail where it's coming in.