Plus AND Minus 12v from AC to Thermostat

hiker108 wrote:
I have a Dometic A/C and a Dometic single zone thermostat. The thermostat requires plus AND minus 12 volts. The schematic of the A/C control box indicates that the plus AND minus 12v come from the power converter and are passed on, thru connectors, to both the A/C control box and also to the thermostat.
F
Where does the minus 12v come out of the converter ?

If I unplug the plus and minus 12v connector to the A/C control box, the voltage at the thermostat drops out. Why?

HELP!

Thanks

I’m not sure if you are confused or just using the wrong terms. There is no minus 12V in an RV system. Minus 12V would be 12V below zero or 24V below your 12V output. This is different from the 12V negative (from battery negative) and 12 positive (from battery positive) leads that make up the RV 12V system.