[JRTJH]

An E1 "loss of communication" error message is typically a loose wire (most often the orange wire) either at the back of the thermostat or in the rooftop unit. The orange wire (in the rooftop unit) can be found by removing the filter and using a flashlight, look up into the return air chamber. BE SURE TO TURN THE A/C OFF AND ALSO TURN THE CIRCUIT BREAKER OFF !!!! Most of us just unplug the trailer's shore power cord (to be safest).

Locate the orange wire, retighten it at the thermostat and twist it back into the wire bundle in the return air duct and you should be OK. GOOD LUCK