Pull the motor out, probably only two bolts and test it with a 12V source. You'll have to ground the case. One wire is retract and the other is extend. My wife is on the way home right now with a new one for our main slide--$250 at the local RV center. You can get them online too. Replacements come with the gears.
Arctic Fox 25Y Travel Trailer
2018 RAM 2500 6.7L 4WD shortbed
Straightline dual cam hitch
400W Solar with Victron controller
Superbumper