Electric Tongue jack not

If the motor runs but the jack doesn't lift then you may have to replace a broken shear pin in the gear box. Sorry, reread about no-run situation.

Disconnect battery. Then using the supplied manual handle, raise (or lower) to clear the down (or up) limit switch. Then try electrically again.

have a volt meter? check the switch?

How did you check those fuses?
Visually or with a voltmeter??
Visually can hide actual bad fuse

Have you verified you have 12VDC from battery to the tongue jack?
Use voltmeter and confirm

Possible the wire crimps failed. Go back to the fuse coming off the jack and press the wires back in. They just need to make contact for the jack to work.

Also make sure someone didnt install the normally black colored jack wire to the negative terminal. Easy to do because i looks like a ground wire.

Clean all terminals. The jack grounds itself.

If easy you can remove the switch on the jack. See if the switch is seeing 12v. Make sure the switch itself has continuity.

Battery charged?

State of charge?

no 12v. brushes shot in motor? bad up/down switch. corroded spades on switch. and the last,just died. one more,,,,, bad ground to frame.