I have checked the fuse and it is fine. I pulled the switch on the drivers door and check to see if power was coming to it and yes there is power to the switch . I was wondering does the passenger side door switch get its power from the driver side switch. I can not figure out what is wrong.
This is a 1991 Mustang Fastback

 

The switch also has to have a good ground connection. If you want to , check if you are getting power to the passenger side switch and motor.