Got the E1 error. Did the initialize and nothing. Turned unit off at breaker and pulled 12v fuse. Did initialize and it started back up.Before I do the initializing I unplug and plug in the phone cord that goes from the tstat to the unit at the unit.The issue is I have to do this every few days. This has been going on for about 8 days now. Any ideas on what could be causing this or what I need to check next?Thanks

E1 means that the COMMUNICATION cable from the wall Tstat to The roof AC control module is open or missing/bad connection. This is the 4 wire cable that looks like a Phone cable. It is NOT a phone cable. It is wired in reverse from a phone cable. Most common problem on a unit more than 1 year old is the Phone type plastic modular connection at the roof AC area is corroded from the humidity from the Upper AC unit. You don't state what year model RV or model roof AC. I ALWAYS replace the RJ11 ends behind the wall tstat and at the roof AC. That removes a possible bad connection. If the upper modular is corroded you have found your problem and replacement is also required. If this does not fix the Intermittant problem then the cable from the wall tstat to the roof will be suspect. DougPS, IF you have Penguin model AC units, then the odds of corrosion on the connection by the evaporator is almost 100%. Replace all connectors if you have more than 1 roof AC unit.

Thanks Doug our living room unit has been giving us trouble since last summer.

Doug, thank you for the info. I went up and cleaned everything again and this time taped the wires in with electric tape. So far so good. I can't find a model number without going on the roof and taking the cover off, I did the cleaning and taping prior to reading your post. I have serial number the factory wrote down but it is very hard to read...2016 Bighorn 3760EL. SteveI will see if I can cross reference the model and serial number with dometic

I found a pic of the tag.Service parts for HIGH PERF HEAT PUMP, 15K BTU,WHITE, CCC2 T-STAT REQ'DModel #: 551816A711C0Product #: 991762941Got this off domestics site on a parts search

You do not have a Penguin model. What did you tape off?????? Did you actually see the Phone type quick connects? If you have 2 AC units, either one can cause your problem with communication. The phone type cable usually goes from the Zone 1 Roof AC to the Wall tstat. Then there is a phone type cable going from the Zone 1 to the Zone 2 control board. On motorhomes Zone 1 is the front AC. On 5th wheel's the Zone 1 will be where the Living room is located. Doug

Dometic A/C and CCC1 Tstat E1 error | Good Sam Community

stickdog
Explorer
Mar 29, 2020
Thanks Doug our living room unit has been giving us trouble since last summer.
dougrainer
Nomad
Mar 29, 2020
E1 means that the COMMUNICATION cable from the wall Tstat to The roof AC control module is open or missing/bad connection. This is the 4 wire cable that looks like a Phone cable. It is NOT a phone cable. It is wired in reverse from a phone cable. Most common problem on a unit more than 1 year old is the Phone type plastic modular connection at the roof AC area is corroded from the humidity from the Upper AC unit. You don't state what year model RV or model roof AC. I ALWAYS replace the RJ11 ends behind the wall tstat and at the roof AC. That removes a possible bad connection. If the upper modular is corroded you have found your problem and replacement is also required. If this does not fix the Intermittant problem then the cable from the wall tstat to the roof will be suspect. Doug

PS, IF you have Penguin model AC units, then the odds of corrosion on the connection by the evaporator is almost 100%. Replace all connectors if you have more than 1 roof AC unit.

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