Dometic Dual Zone Thermostat Not Recognizing Zone 2 AC

[Flatbroke]

Okay camping warriors i need some desperate Help. I have a 2012 Montana 5th wheel Model 3585SA. We to cut both AC on to start packing, well would not my back unit come on but the one up in bedroom, would not come on. It was reading a code of E7 . I reached out to domestic customer service, they said try a reset, so i did, still will not recognize Unit 2. its like it don't even exist. So called them back and they So they said it sounds like the communication cable needs replace, must not be communication. They gave me the cable number and have ordered and replaced both, Still will not show that, So ordered a new mother board for the unit and changed it out well thermostat still will not recognize zone 2 AC. So called them back and after explaining it all over again. they said the same thing again. So with that said is there any way that may RV Dual zone thermostat could be bad to where it's just not recognizing that one zone, That's the only thing i can think is left we have not changed Any help are other ideas to help fix it, would be Greatky appreciated

 

[c214dick3]

I replaced my dual zone thermostat from Amazon. Simple plug and play but the new ones are set up for four zones. Just toggle through for zones 2 and two.
My problem was the main a/c fan only stayed on one speed. All good now.

 

[c214dick3]

I replaced my dual zone thermostat from Amazon. Simple plug and play but the new ones are set up for four zones. Just toggle through for zones 2 and two.
My problem was the main a/c fan only stayed on one speed. All good now.

Zones 1 and 2

 

[c214dick3]

Zones 1 and 2

 

[ChuckS]

You have ttwp cables involved for the CANBUS comm lines from the Tstat to Zone 2..

You stated you replaced both RJ11 cables ( phone wires )

The Tstat .. Dometic CCC2 has one cable that runs from it up to Zone 1 AC control box ..

The second phone cable runs from Zone 1 to Zone 2 control box

The Dip switch settings on Zone 2 control box must be set properly for the Tstat to be able to find it ..

Also … have you verified there is 12 VDC to the Zone 2 control box? It should be getting its power from the (Red/Blk) wires on the RJ11 plug from Zone 1 control box to Zone 2 control box

If it has no 12 VDC the Tstat can’t see it across the CANBUS

Also.. when you replaced the cables and then the control box did you do a Tstat RESET ?

If NO you must do this to establish a new comm link between eveything , anytime you break a CANBUS connection you mist do a reset