The 110v plug mduff mentioned may be on a different circuit than the other items you mentioned. Remove the cover for the frig on the outside of the TT and plug a lamp in to test for power. If you have a fuse blown another way is at the power center see if one of the red lights is on if it is this indicates a blown fuse.
I think the light inside the frig is 12 volt so you will have the inside light when on Propane.
The circuit is not seeing the 110 volts so it is trying to go to prpane operation thus the check light.
Good Luck and enjoy.
Dale & Terri, Lulu & Tiki (our Chihuahua's), New rescue puppy Prince - Pom/Pug mix.
2013 Tundra, Double Cab, 5.7, TRD Off-Road, 4X4, Full Tow Package
2013 Wildwood T26TBSS - Sold
2000 Gulf Stream Sun Voyager M-8357 MH, Ford Trident V10 Gasser, 35 foot.