Dick_B wrote:
The fridge and lights work off the battery (12VDC). The outlets work off campground voltage (120VAC).
With that in mind try finding the fuse that controls the lights/refer and be sure the wires to it are tight. You might try installing another fuse of the same rating. When the lights go out test the voltage at both sides of the fuse. If there is voltage on both sides the fuse is good.
Also, our TT had a secret 12V circuit breakers located under the chassis. When it tripped one had to reset it by hand. We replaced it with one that will reset itself after tripping. Could your rig have the same thing? The symptoms point to something like that.
It's got to be the breaker in regards to the auto reset that some systems use.