If i remember correctly, the non-ducted (at least the one I had on my old RV) roof top units run line voltage(120v) through their controls, While the remote stats on the ducted units are running on low voltage (12V).
I rewired my roof top to bypass the internal controls on my old camper. I removed the shroud from the ac unit and added some relays in a small junction box inside the housing. Its been a long time, but I think it took 3 relays. One for the compressor and two to control the two speed fan. you then remove the wires from the back of the stock controls and connect them to the relay contacts. Then you have to find a way to run some thermostat wire up to the ac unit from the stat location. you can then use an RV thermostat or a programmable household one as long as it powered by batteries (the hard wired ones use 24 volts AC). connect the stat wires to the relay coil terminals.
All in all quite a bit of effort, but the best part was the fan would come on and off with the compressor. with the stock configuration as long as the ac unit was on the fan would run continuous, just the compressor would cycle on and off.
I am betting now there is probably some wireless remote thermostat that could be adapted...
Problem is also when you work in engineering, there is a internal need to see if everything can be improved, even if it already works...lol
Dave
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