2015 Wildwood 327 ck, two ACs with two Dometic Thermostats, one in kitchen/hallway and the other in bedroom. The thermostat in bedroom has an error code E4. I have read the user's guide and got the operating instructions online but it doesn't tell you what to do about it?
E4 is an error in the outside temp sensor for heat pumps, but has been discontinued in later models. Some older units had issues with flashing that error. As long as you don't have a heat pump the furnace and A/C should still work.
There are a couple of things to try.
1) Pull the fuse for that thermostat power for a minute or so.
2) Initialize the thermostat according to the manual.
If that doesn't work you have either a bad thermostat or control board.
Salem 29RKSS Pushing a GMC Sierra 2500HD!
Gotta go campin!