[cwl1979]

Carl, just a a note to store in memory, some relays, added by coach builder, are there to convert a 12 vdc thermostat signal to a ground signal.  Many A/C circuit boards send 12 vdc thermostat signals.  The AH zone wires are ground signals.

Take a jumper cable that is connected to ground and touch the living room thermostat connection.  Tthe zone pump and living room fans will come on.

Not being there, I can not say this is connected to your problem.  Just sharing info.

I do believe this is exactly the problem and why they used the automotive relays to reverse the signals for the salon and bedroom thermostats.