Sounds like you have the same system as me. A PIA.
Easy first check is the fuse. Not likely blown unless you have held the switch too long.
Most likely fault is a stuck knife valve at the tank. You will have to cut yourself an access panel out of the trailer bottom. Biggest challenge there will be to locate where the valve is & cut a panel big enough to open & get working room.
On one side of the knife switch is an allen screw to manually open the valve. Most likely it is stuck & needs just a slight turn to make contact & the motor will work again.
All of this seems daunting the first time around but once you see what to do & how to do it, no real big deal.
The underbelly will have to be taped up & the valve will likely stick again especially if use is not very frequent. Don't use duct tape. It is a PIA & leaves a sticky residue on the underbelly material. Best thing found so far is the silver metal tape. Not the thick type that has a backing to peel off.
Take it to the dealer as a very last resort. Given what that valve handles you will think that they have put a roto rooter in a part of your body by the time they are finished with you.
