Dometic Digital Thermostat Conversion
This summer, I installed the Dometic 3313195 T-Stat and relay box and removed the analog T-Stat. I did not hook up the separate 12v furnace because we just needed AC. The AC works fine, but when I w...
Forum Discussion
"This weekend I will check to make sure that I have continuity from the T-Stat to the circuit board. I assume that one is supposed to register 12v positve and the other will be 12v neg."
NO, You will have 12 volts at the AC control board and the other wire will be DEAD. It supplies the 12 volts BACK to the furnace to engage the start relay on the furnace. If you have 12 volts on 1 wire, just connect them together at the AC control board. Then go to the furnace input harness. There are 4 wires. 1 wire is 12 volt positive. 1 wire is 12 volt ground(neg). then you have the 2 blue wires. One will have 12 volts and the other will have 12 volts when the 2 wires are connected at the Roof AC. So if you have 12 volts at 3 wires going into the furnace your problem is IN the furnace. Doug
NO, You will have 12 volts at the AC control board and the other wire will be DEAD. It supplies the 12 volts BACK to the furnace to engage the start relay on the furnace. If you have 12 volts on 1 wire, just connect them together at the AC control board. Then go to the furnace input harness. There are 4 wires. 1 wire is 12 volt positive. 1 wire is 12 volt ground(neg). then you have the 2 blue wires. One will have 12 volts and the other will have 12 volts when the 2 wires are connected at the Roof AC. So if you have 12 volts at 3 wires going into the furnace your problem is IN the furnace. Doug
