Im trying to fix the window motor on my 86 f150 i got the motor removed and hooked up the one i just got from the junk yard and it will only let the window up when i press down it does nothing i also checked the motor that came with the truck and the same thing happened so i assume there is a problem in the wire harness. any advice on this issue would be greatly appreciated

 

Have you checked the switch? Maybe hook it up backwards and see if it does the same thing.

 

I tried that but it still only works in one direction

 

If the switch works and both motors do the same thing I would look for power to the "down" side of the switch or a bad ground.

 

I have the exact same problem! Motor works, switch works but motor only goes in one direction. Anybody have a resolution to this issue?