Both front and back motors are not that hard to fix.
the front ones
Busy rebuilding the 2 front PW motors of my 71 and soon the rear ones.
And as expected as 99% of the time on 71-3, the electric side and motors are just fine.
It's the gears and the cylinders that are either locking the motor or the motor turns but glass doesn't move.
Just 3 screws to remove to uncover the gears and chances are you will get to see the same as on this pict.
The cylinders (bushings pellets) that are supposed to be made of soft plastic, acting as some kind of clutch in case the glass would be blocked during its travel and potentially fail/break if the motor would not stop. They often get hard and explode in tiny bits if they sat unused for a long time, while there is nothing wrong with the motor on itself.
You need 3 per motor. Sometimes the broken bits may break the plastic holder. You can buy these as well, but the kits are usually more expensive.
here is what I've ordered
https://www.ebay.com/itm/372646485348
So as the PW motors are expensive and "broken" in 99% of the cases because these these cheap little guys
I'd look first and likely, if you do not see 3 nice cylinders, you'll have an operational motor back for 8 buxx.
Edit: on most Ford, you can just pull the center gear out (the one I hold left on the pict), but in our cars some may have a tiny o-ring on the axle, so you would need if the center gear doesn't come right off, to lift it a tad, gently with a flat screw driver till it "pops" out.
As for the rear flat ones. Pancakes, it's often just a good cleaning/de-rust story or a set of brushes
