An RV thermostat is a special part, not a shrunken house thermostat. Almost all of them run on the RV's 12 V house system, most control both the roof air conditioner and the propane furnace, and many talk digitally to a control board inside the air conditioner. A replacement has to match that system.
RV Thermostats Explained: Types, Why a House Thermostat Will Not Do, Replacing One
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At a glance
- Why it is special: the wall control is a low-voltage switch. The household-strength power that runs the roof unit is switched up in the ceiling, not at the thermostat.
- First check: a blank display calls for the 12 V fuse or breaker and a voltmeter reading of about 12 volts at the thermostat's two power wires.
- Replacing it: buy what the maker lists for your exact original display, because each aftermarket model covers only certain systems.
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Does an RV need a special thermostat?
Yes, in nearly every case. On Coleman-Mach systems it works the ceiling assembly, which switches the air conditioner's 115 VAC circuits through 12 VDC relays, according to Airxcel's 7330 thermostat instructions. Most models run both the roof air conditioner and the furnace from one display.
Most run on the RV's 12 V house system, but not all. Coleman-Mach's WiFi thermostat compatibility guide includes 24 VAC systems, and some older Coleman analog displays run on their own batteries.
Tip: On Dometic single-zone and Comfort Control Center 2 systems the thermostat is part of the air conditioner's control system, not a separate switch. Error E1 means the display has lost contact with the board in the air conditioner, and the system shuts down.
Analog, digital or zoned: which one you have
The type on your wall decides what can replace it.
- Analog. A temperature lever plus switches for cooling, furnace and fan.
- Digital single-zone. Dometic's Single Zone LCD comes as separate models for cool and furnace, with heat pump, or with heat strip. Airxcel's 9430 comes cool-only or heat/cool.
- Zoned. Dometic's Comfort Control Center 2 runs up to four zones, one per air conditioner.
- Basement and dual-stage. Motorhomes with a basement air conditioner, often Winnebago or Alfa coaches, use dual-stage controls.
Tip: A heat-pump roof unit needs a control that knows about the heat pump. With Dometic that is a different model number, not a setting. Dometic also locks heat pump operation out below 30 F, which is normal and not a thermostat fault.
How do I tell if mine is bad?
Check power first, then the display's codes, then the outputs with a voltmeter.
- Blank screen. Make sure the 12 volt system is charged and the breakers and fuses are on, then measure for about 12 volts between the thermostat's two power wires, as Micro-Air advises.
- Fuse. Some displays carry their own fuse, such as the 2 amp fuse on the Airxcel 9430's base. A blown one points to an appliance problem, so find the cause before fitting a new one.
- Codes. Dometic's E7 means the air conditioner has lost its 120 Vac power, which is an air conditioner side problem, not the display.
- Output test. On 12 volt terminal-block systems, each output reads about 11 volts DC when the thermostat calls for that appliance and about 0 volts when off, per Micro-Air's EasyTouch RV 352 manual. A live output with nothing happening means the fault is in the appliance or its wiring, and Micro-Air recommends an RV technician for that.
Two normal delays get blamed on the thermostat. The compressor waits before starting: about two minutes on Dometic, three on Airxcel. A furnace that runs its blower and then quits has locked out at the furnace, and Dometic and Suburban both say not to keep cycling it from the thermostat to force ignition.
What can I replace it with?
Buy the replacement listed for your exact original display.
| Original display | Listed replacement | What it needs |
|---|---|---|
| Dometic CCC 2, 10 or 12 buttons | EasyTouch RV 350 | Existing phone-style modular jack |
| Dometic single-zone LCD or capacitive touch | EasyTouch RV 351 | Terminals 12V+, COM, ground |
| Dometic CCC, 5 buttons | EasyTouch RV 357 | No match for the 4-button single zone |
| Dometic 3106995 analog | EasyTouch 359 | One wire moved in the AC control box |
| Coleman-Mach and Airxcel 12 V single zone | EasyTouch RV 352 | Not for 24 VAC systems |
| Coleman-Mach dual-stage basement | EasyTouch RV 356 | Single zone, dual-stage wiring |
| Furrion FACW10SA, FACW12SA, FACW10ESSA2, FACW12ESZA2 | EasyTouch RV 353 | Model sticker is inside the display |
| Atwood Air Command, label C174.LED | EasyTouch 358 | Fused 12 V feed and ground run to the wall |
Compatibility from the Micro-Air EasyTouch RV documents. Two thermostats mean two replacements, because each zone's display talks to a board in its own air conditioner.
A household thermostat is not a swap for a control wired to an air conditioner. No maker says yes or no, but RV displays are built for the RV's control circuit and many talk digitally to a board in the unit, so pick one the air conditioner maker or a listed aftermarket maker names. Airxcel warns that parts not tested with its units void the warranty.
A furnace-only circuit is the exception. Dometic's AFM series furnace manual asks for a thermostat rated for 12 VDC or 24 VAC with at least a 1 amp rating, and Suburban's 161401 digital thermostat suits any RV furnace needing a 12 VDC control circuit of no more than 2 amps. If the furnace itself will not light, a new thermostat will not fix it.
Can I do it myself?
The wall swap is 12 volt work, but the makers disagree on who should do it. Micro-Air writes its manuals for owner installation, while Airxcel and Suburban say their thermostats should be installed by trained technicians only. Micro-Air's order:
- Unplug the RV from shore power.
- Switch off any converters and generators.
- Open the 12 volt breaker or fuse feeding the display.
- Photograph the wiring at the back of the old display.
- Transfer each wire to the terminal with the same name.
Tip: Match by terminal label, never by the color of the wire in the wall, which can be any color. Coleman and Airxcel display pigtails use red for 12 V positive, blue for ground, yellow for the compressor and white for the furnace. On Furrion systems the four tagged cables from the control box must not be crossed, and miswiring a Micro-Air 351 makes it reboot constantly.
Stop at the ceiling. Any swap that means opening the air conditioner's ceiling assembly or control box, such as the Micro-Air 359 install, puts you next to the 115 VAC side. Furrion and Airxcel both limit that work to qualified technicians.
Common questions
How do I know if my RV thermostat is bad?
If a Micro-Air display has gone blank but the app still controls it, open the 12 VDC breaker or fuse for a few seconds and restore power, because electrical noise can corrupt the screen.
Will any thermostat work in an RV?
No. Some originals have no aftermarket match at all, and Micro-Air's lists are not exhaustive, so it asks owners to contact it when a model is not listed.
How do I tell whether it is the thermostat or the air conditioner?
Dometic's pre-service checklist runs through the generator, the shore line, the 120 Vac fuse or breaker, then the 12 Vdc fuse or breaker. The 120 Vac circuit feeds the air conditioner and the 12 Vdc circuit feeds the control.