Power Window problems:
Remove the door mounted speaker & the upholstery panel to gain access to the motor. There are 3 screws (5/16" hex head, I think) that secure the motor in place. Remove them and the motor comes out without any problems. Once you remove all the screws from the motor, and it falls away from the gear teeth on the arm for the glass, the glass will move up and down. You may need a helper to hold the glass once the motor screws are out, since the gear on the motor holds the glass from sliding up or down
The motor is the same for left side or right side, only the gearboxes are different. If you can't find the complete assembly for the side you want, you can get either side and use the old gearbox on the new motor.
The gearbox has 3 plastic rollers that are a safety clutch to prevent possible injury if the window is rolled up while something or someone is hanging out the window. The plastic rollers will often disintegrate into chunks of plastic and the window will no longer roll up or down. The Help! section of your local auto parts store will have the replacement plastic rollers
Stuck with door lock actuators that don't work and don't want to pay the $50+ for a new one? Tried the junkyard ones and found that they last six months and freeze up?
A new actuator for less than $5. Fix one side for $18, do both sides for only $25. I don't sell parts, I don’t make any money off of the upgrade, I just tell you how to do it cheaply and easily.
Here’s a picture of the new actuator installed:
See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Engine Information Everyone should bookmark this site.
While inside the door, check the ground wire (it's about right in the middle of the door, lower than center, IIRC).
Also, you might try opening and closing the passenger door while an assistant uses the driver's PW switch. If the locks and window operate intermittantly while you move the door, there might be a weak wire in the articulated boot.