Some also have a reset switch in the w/h panel outside. Make sure they are "in"! Also check the connections outside. I had a customer bring in their TT with the same complaint. It ended up being the connection in the w/h panel was terribly corroded. A quick simple clean, and all worked fine. (Not sure why it didnt affect the LP side, but it didnt, just the electric.
I started with nothing, and still have most of it left
2001 Jayco KIWI 23B
2003 Jeep Grand Cherokee 4.7 AWD