Are your battery connections good? I think the battery has to have a good connection for the LP to work?
I don't know what year yours is but ours was a part of a recall Norcold had with the high temp sensor. The recall box got wet and failed and our fridge was showing an error code (LI oP) on the display on the front. Google your year and model #. There is a lot of information online about Norcold fridges, manuals included. Maybe call Norcold directly. We ultimately took ours back to the dealer to diagnose and repair. Norcold supplied the replacement parts and also paid for the labor to have everything fixed.
2010 Keystone Montana 3455SA Quad Slide
4 Goodyear G614's
2017 RAM 3500 DRW 4x4 Crew Cab
6.7L Cummins® Turbo Diesel
B & W Companion Hitch
All Made In USA
*I chose the road less traveled... Now I don't know where the hell I am*