rear/side power window on 1971 442 quit working halfway up and is now stuck in that position....how to bring it back down without power ?

 

No computer, so no hack.

Do all windows not work? Fuse.
Does it work with one switch and not the other? Switch.
Will the motor run with 12v battery power applied to it? Wiring.
Does the motor head turn but window does not move? Mechanism.
Will the motor take power but not move? Windings.

Check all that stuff. Lube the tracks and the joints. I think, if you take the motor off, the window will freefall to the bottom of the track. Ghetto fix, take motor out, drop window.

 

You need to open up the door where you can access the track. You may have a wheel that is worn out or it just might need some grease. You might also have something off the track which is binding. You can usually tell right off if there is something wrong. In any case if it's the motor you will have to get in there to replace it.