E1 error code on my dometic thermostat

This error indicates a loss of communication between the thermostat and motherboard. Try resetting all breakers first by leaving the unit without power for at least 5 minutes. You may also have to disconnect the 12v from the thermostat. There is also a manual reset procedure by holding the mode button for a period of time.

AC Thermostat Reset
Well I just found out that you can reset the the t-stat, which resets the computer board in the ac unit.
Turn the tstat off
Once off push and hold the mode and + at the same time for approx 4/5 seconds
and - - (dash dash) will appear.
That will reset everything.
Then you can turn it back on.
Problem I was having was the furnace was not turning on but if you turned it off and then back on it would work fine.

I think this solved my issue.