Not a dumb question at all. All fuses (that I can find) are fine. Resettable Circuit Breaker in the battery bay reads full voltage across it, so not that, either. I have not yet crawled under to check voltage at the motor, but that's on today's to-do list.
Speaking of crawling under the rig, I did that yesterday. Cut two access panels into the underbelly to locate the slide motors and attempted to manually crank in the non-working slide. Lo and behold, the "bad" motor has NO HEX EXTENSION on the motor/actuator. That means nothing to attach a socket wrench to for manual operation. Sigh...
Surely the other side has one(?). I'll just move it over to the nonworking slide motor and crank it in. NOPE! Not only does the other (working) slide motor also have NO hex extension, but it is also mounted almost all the way up against the frame! Even if it did have a hex extension, there would be no room to use a wrench to operate that slide, either. WHO DESIGNS/ENGINEERS LIKE THIS?!?! Silver lining - at least I discovered this little delight while the rig is in our driveway and not in a campground or out in the boonies. Monday will be an interesting day as I call dealer, Keystone, Lippert, Good Sam, Dr. Phil, and anyone else I can think of to vent my frustrations and get this nonsense resolved.