Dometic Duo Therm Thermostat / Zone 2 issue

[DunnInn]

We have a 2003 Newmar Dutch Star with 2 Penguin heat pumps and a 5 button Dometic Duo Therm Thermostat. It was working, but suddenly couldn't see zone 2. It would blink 2, but wouldn't allow any input. Being the Technologically challenged people we are, we did the system reset at the thermostat thinking that might cure the problem. Now you don't see zone 2 at all. I've looked at several of the posts that say it's probably the comm cable from unit 1 to unit 2 or the connectors on the cable that is the problem. Would REALLY like to have the wiring diagram for that comm cable - I know black/red/green/yellow for the wire colors, but what exactly are they attaching to? Thanks for any help.

[Flute_Man]

Mine has like a telephone cable which is a digital communications cable. Might try unplugging and plugging the cable back in at the thermostat and then take The inside air conditioner covers off and unplug and plug that communications cable. If you can find someone to help you you can take the outside covers off of the AC units and unplug and replug the cable back in there on the circuitboard. If that does not correct then see if you can find a mobile tech to come and troubleshoot. You may call me if you wish and I will try to help you over the phone.