Easiest way I have found to run down the problem is take the door panels off one of the sides that is not working and disconnect the window motor two wire connector. Take a test light and touch one of the wires coming from the main harness inside the connector. Have an assistant operate the power window switch for the window you are working at. One wire will light when it supposed to go up, and the other wire will light when it supposed to go down. If that is working as it should, then the window motor is to blame. I had three bad window motors on my Coronet when I bought it. If your handy, you can take the motors apart and clean/lube them up. I fixed two out of the three bad ones that way