OXS sensor and water leak

[Hiok-Tiaq Ng <htng@aries.ece.cmu.edu>]

Hello everyone, a friend of mine has an '84
5000 sedan and his OXS light is on and he wants 
to reset it himself. How could it be done? 

Also his car leaks. Driver's side footwell is wet
after each rainstorm without even driving the car.
He says the window molding seems to be in good shape.

Anyone experienced these before and has a good remedy?
I'll forward replies to him. Thanks everyone.

Tiaq
htng@aries.ece.cmu.edu