They might just be stuck. It happened a few times on mine. The motor would try to start and then would pop an automatically resetting fuse and everything would stop.
I ultimately had to use the manual crank and force it to turn. Once I got past the first inch or two, the motor could do its thing. Once it was down, I lubed the hell out of the "worm screw" or whatever that cross-bar is called. Ran it up and down and sprayed dry lube on it liberally.
Officially a SOB with a 2022 Jayco Precept 36C
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| Was a Fulltime Family for 5 years, now we're part-timing on long trips