One of mine stopped. I trouble shot it and found out what it was, just haven't done the fix I want to do to it yet.
What I found is common as well as there is a TSB about the seat getting stuck in a certain postion and stalling the motor.
There is also a gimic automatic ckt breaker built into them.
They go bad,,, IE trip too early.
There's a access hole in the plastic end of the motor.
If you put the likes of a paper clip in there and short it out, and the motor works, you can take the motor out, short it out, but add a fuse or DC ckt breaker in series with it, about 10amps or so.
You can't buy the motors from DC, tried that.
The only other choice I see is getting a lower half of a seat from the junkies would be a good thing