Hello,
When you say you checked your extension cord, what do you mean by that? Were you able to ohm out the wires to determine that you didn't have an inline break anywhere? Just because you changed outlets to a known good outlet, doesn't rule out a problem with the cord, switch or motor itself. If you have access to an ohm meter, volt meter, continuity checker or even an inductive power sensor ( electritians use these all the time to find live power feeds) then you may be able to determine where the problem lies.. I did a cursory search for a wiring diagram for that particular model but was unable to locate one. Not having that information means I am only speculating what your problem could be. Is there a reset button or popout circuit breaker on that model that may have tripped? If so, reset it and try it again. If not then you may need to do some troubleshooting of the hardware itself. Not sure I've helped you at all but I tried.. Hope you can trace out the problem... Good luck..