water leak in my 94 ranger

Hi guys new to the forums and this seems to be the right place to post, I have a 1994 ranger standard cab short bed, 5 speed manual locks ect. ect. and I got this truck from my dad's friend it had been sitting in his yard for 2 years or so. I first got it payed to have the motor and trans un seized but my new problem is when I wash the car or it rains hard water comes in under the firewall it seems and goes under the matting on the passenger side, I was looking under the hood today and it looked like the gasket around the blower motor that's against the fire wall (I think it's the blower motor) if the gasket is broken/coming out could it be that water is going in through the top and going into the truck? Any help/ideas of where the water is coming from I hope it's there so I can fix it but thanks in advance for all your help.