If the levelers are Lippert, go to their website and look for the manuals.....
https://support.lci1.com/hydraulic-l...rized-leveling
If you have no lights under any conditions on the control panel, start with why. My guess is that the DC breaker that supplies the hydraulic unit (and the panel) tripped or the large fuse blown.
Or.... On some older units Lippert also had problems with a timer circuit board that was embedded in the main control harness. Caused a total dead system except when the engine was started and the unit would cycle to make sure the jacks were up. Lippert has great tech service and I used the Chat and found this out in 15 minutes. Replaced the harness good to go.
Good luck.