Not sure about your model. On mine the breaker for system is in battery bay, it is a hard to see little red lever. But from what you are describing it sounds like it may be the diode issue on the levelling system wiring harness control board, assuming you have the Lippert system. There are posts on here for this issue, find the black and white wire on left of pump and remove it, then go back in try the jacks again. There is a YouTube video from Thor that explains this procedure.
2014 Georgetown 335DS
Lincoln MKX toad