Dometic thermostat troubles


Active member
Our trailer has Dometic A/C, Suburban furnace, and a Dometic digital thermostat. When using heat the degree offset from set temp to heat on to heat off has always been far too wide, you're roasting when it finally turns off. There's one option that reduces the temp delta but something is unhappy in the combo and it does a rapid toggle that's not right. I decided to replace said thermostat with a household digital thermostat as recommended and documented on various YouTube vids and rv threads. What a surprise to learn after removing the thermostat to find only 3 wires. Seems the Dometic thermostat is wired into a control unit inside the Dometic A/C unit that also controls the furnace. It's apparently possible to replace the control unit with a different one that includes splicing the wiring, not plug and play. Electrical is not my thing so out of luck. We'll use electric heaters when we have shore power. Maybe for the best as the furnace roars like a jet engine.
Is there a remote temperature sensor other than the one in the thermostat? Our trailer has two sensors and the remote can really mess with you if you don't factor it into your settings.
There's a sensor in the AC plenum that I think is a freeze sensor. Our trailer isn't big enough for 2 temp sensors. 😁
Do you get cold/hot spots in the trailer? I ask because we keep a small fan running in the bedroom door to avoid hot/cold spots in the trailer. Without the fan, you'll get hot/cold spots.
The thermostat is in the bedroom and the delta between on and off heat is way too wide and the bedroom gets hot while the rest of the trailer gets warm. It's also more of an on/off switch for the AC. Just seems like a crude piece of equipment. Since we have electric at all of our stops on this upcoming road trip we're taking 2 small 1500 watt space heaters that will do fine. I need to research if there are better Dometic thermostats that are plug and play with the control box I have.

This is the unit.

dometic  thermo.jpg
Last edited: