You can try giving the motor a tap and see if it will make it work, the motor stops all the time is the same place and some times the bushing gets burnt and stops working. If that doesn't do it there is a pin in the linkage with a cotter key you can take out to let the steps down. On mine I can't get the pin out with the steps retracted so I unbolt the plate the motor is attached to, to work on it. DO NOT TRY AND WORK ON IT WHEN IT'S HOOKED UP TO POWER IT CAN DO REAL DAMAGE TO BODY PARTS IF IT STARTS. Un plug all the connections before trying to take it apart.
Most of the motors on the older ones are Ford power window motors and cheaper to buy at the auto parts store. You mite try and unplug all the connectors and replug them to see if that will do it.