My step stopped operating either direction. Read up on the LCI trouble shooting, bought the recommended pigtail and determined the motor was "bad". $150 later had a new motor assembly installed, problem fixed.
Opened up the "bad" motor, everything looked good, brushes, commutator, gear, etc. However, could not apply power at connect and make it run?
Long story short, there is a capacitor in series with one of the brushes that is open. If power is connected directly to the brushes, motor runs well.
I think the capacitor is a "soft start" component so, there isn't a hard jolt when motor starts. Working to find another one now. If I can fix it, I have a spare.
Things an engineer with time on his hands get into