94 GP Passenger Power Window Help

My Passengers Window wouldnt go down. I removed the power plug from the motor and checked for power to Ground. I was getting power to ground in both directions. I then removed the regulator / Motor assembly feeling the motor was bad. I removed the motor from the Regulator and pluged it back in and sure enough it would move one direction but not the other. SO... not thinking to a great deal I automaticly assumed bad motor. Went and got a new one and guess what? It also only goes one direction. Now I check into the voltage more closly thinking maybe it needs to be grounded but it dont. My problem seems to be in one of the switches??? Using a voltmeter if I stick the + probe in one socket and - in the other ill get 13volts. If I switch the + and - leads I get nothing?? BUT If I put one probe to chasis ground and + to either wire Ill get 13volts from both. What could be wrong? The master switch on the drivers door possibley?