Dometic AC zone issue

[Junior01]

I have dual dometic roof ac units and a 5 button DuoTherm therm. I have not been able to get the thermo to recognize the front AC unit. I have spoken with Dometic, the dip switches are set correctly, I have replaced the control panel on the front unit and still no luck. I also set the dip to show the front as zone 2 and rear as zone 1 and it will correctly recognize the rear AC according to how the dip switches are set, but never recognized the front unit. Any ideas what the issue is? I dont believe it is communication, or thermostat, nor the control panel;.

[Junior01]

Thanks for the info and tips.

[CA_Traveler]

Run a temporary wire inside the rig to eliminate wiring as the problem.

[MPI_Mallard]

I just went through this **** with two NEW A/C units, It's a good bet that the thermostat has bit the dust however just to be sure you should check the phone wire that connects the A/C unit for continuity to the other to make sure it's OK but my bet is the thermostat. You might want to make sure you can return the unit in case it's not it.