4 Ways to Tell if an RV Thermostat is Bad

Check/Test TV Thermostat

It might surprise you to learn that your RV thermostat can turn faulty, causing inefficient operation of your RVs A/C and heating unit. Most thermostats have a service life of 10 to 15-years, and if you recently purchased a pre-owned RV, you might experience some issues with the thermostat eventually.

Thermostats can end up malfunctioning due to old wiring, dust, or a poor wiring job on a replacement unit. Whatever the reason for your thermostat is going bad, it sure makes life uncomfortable for the occupants of the RV, especially during hot days and evenings.

So, how can you tell if your RVs thermostat is bad? In this article, we’ll look at the common problems associated with the thermostat, and what actions you can do to resolve the situation.

4 Ways to Tell if an RV Thermostat is Bad

Image via TurtleHerding

Problem 1- The Thermostat is Unresponsive or has No Power

The most common issue affecting thermostats is when the unit loses power and refuses to switch on. In this case, the thermostat may have lost a connection to the electrical circuit. The thermostat wiring may be loose, and it may disconnect from the unit during travel.

You may also notice that there’s no change in temperature when adjusting the settings on your RV thermostat. As a result, the thermostat cannot identify the current room temperature, resulting in inefficient operation of the unit.

You might also notice that the display of the thermostat is dim, or it might not turn on at all. There might be damage to the screen, affecting the unit itself, resulting in the inability to adjust the temperature setting.

Some thermostats feature battery-powered operation. If you’re confident that your electrical system is not the fault, then it may be due to the batteries inside the unit failing. Replacing the battery is a quick fix, and it doesn’t require the assistance of a professional.

If you replace the battery and don’t experience any change in the thermostat, then it might also be broken. Damaged, broken, or unresponsive thermostats need replacement with a new unit.

Avoid buying refurbished thermostats. While they might be more affordable than purchasing a new unit, they also rarely come with a warranty, and the chances are that they might end up malfunctioning shortly.

Always ensure that you purchase a new thermostat from the manufacturer or agent. A new unit comes with a warranty, and you can return it for a replacement or a refund if it malfunctions.

It’s not overly expensive to upgrade a thermostat, however installation of some units is best left to an electrician. Even so, budget around $75-$150 for a DIY upgrade, or $300-$400 if you have the work done by a professional.

Some Models to Explore

A programmable thermostat makes life in an RV much more livable.

If you have to upgrade your RV thermostat, here are some digital, programmable thermostats to consider and their approximate cost:

  • Dometic Model 3109228.001 Comfort Control Center. ($166.62)
  • Dometic Model 3314082.011 Comfort Control Center II, or CCC2. Multi-zone for bigger RVs. ($172.05)
  • Coleman Digital Wall Thermostat Model 8330-3862. Includes plug-type wiring connections. (Price not available)

Problem 2 – The A/C or Heater Won't Switch On

If there is no power going to the thermostat, then it could be due to wiring defects, or dead batteries in the unit. Wiring issues prevent the unit from sending and receiving the electrical signals it needs to operate efficiently.

In this case, you’ll need to remove the thermostat from the housing and inspect the wiring for damage. If there’s no apparent damage to the wiring or harness, then you can take the unit to a professional electrician for testing.

Problem 3 – The Heater or A/C Runs Continuously and Won't Switch Off

If you find your heater or A/C unit is always running and won’t switch off, even when you press the power button, it could be due to frayed wiring or the thermostat unit might not have the correct calibration.

In this case, you’ll also need to remove the unit and check the wiring harness.  If there’s no apparent damage to the wiring, then take the unit to a professional electrician for assessment and inspection.

Problem 4 – The Setting Doesn't Match the Temperature Inside the RV

When the room temperature doesn’t match the reading on the thermostat, it’s one of the subtle signs that your RVs thermostat is on the fritz. If you turn the heater up and don’t experience any change in temperature inside the RV, then the unit may need recalibration.

Troubleshooting Your RVs Thermostat

Image via LoveYourRV

In this section, we’ll look at what you can do to troubleshoot issues with your thermostat. There are a variety of things that can go wrong with the unit, but we find that the following solutions fix most problems with your RV thermostat.

If you notice any of the above telltale signs occurring with your RVs thermostat and air-conditioning system, then we advise you read through the following troubleshooting tips for a bad thermostat.

Step 1 – Ensure You Have the Thermostat on the Correct Setting

This step might seem obvious for most RV owners. However, you’ll need to ensure that the thermostat is on the heater setting if its winter, or cool if it’s during the summertime.

Some of the simplest mistakes can cause the most significant problems, especially if this is a new RV, and you have no previous experience in working on these vehicles.

If you find that your heater or A/C unit is continuously running, it’s probably because the setting is “ON.” Find the control panel on the thermostat and switch it to “AUTO.” The auto setting adjusts the temperature to meet your ideal operation.

With the auto mode, the air-conditioned or heater only blows air when the system is heating or cooling the air inside the RV.

Step 2 – Turn the Thermostat Down or Up 5-Degrees

If you’re dealing with this issue during the summertime, then set the temperature to 5-degrees lower than the outside air temperature. Conversely, if it’s the wintertime, then set the thermostat to 5-degrees above the outside temperature.

When turning the thermostat settings up or down, you should hear a clicking sound. Wait for a few minutes, and you should notice the supply register vents blow or suck in air from inside the RV.

Step 3 – Check and Replace the Thermostats Batteries

Many of the new RVs coming onto the market feature digital thermostats. If you own an RV with a digital thermostat, then try replacing the unit’s batteries. You should notice the thermostat come to life if this is the issue at hand.

However, if you replace the batteries, and nothing happens, then the wiring should be your next troubleshooting point. If your RV does have a digital thermostat, its best to replace the batteries every year to ensure you never have to deal with your thermostat breaking down.

Step 4 – Air Blast the Thermostat

Some older models of RVs feature mechanical thermostats. You’ll know it’s a mechanical thermostat because they typically feature a tiny lever that allows you to change the temperature inside the RV. However, mechanical thermostats often run into issues with dust accumulation. The dust can get inside the unit, jamming the mechanical parts.

If you purchase a pre-owned RV with a mechanical thermostat, then this might be the problem causing the malfunction of the unit. Take the cover off of the unit and blow it clean using a can of compressed air.

Step 5 – Test Connections and Wires

If you run through the above troubleshooting list, and your thermostat is still on the fritz, then it’s time to check the wiring. If you have no previous experience with electrical components, then we advise you to seek the services of an electrician.

If you do have electrical experience, then remove the cover of the thermostat, and check the wiring connections into the unit. If there are any loose wires, connect them again, and see if it makes a difference.

26 thoughts on “4 Ways to Tell if an RV Thermostat is Bad”

  1. Natalie Roberts

    Thank you for useful information. Recently displayed temperature in my rv thermostst and the actual temperature felt are different. It made me feel terrible! I thought that it has broken. But now I will test my rv thermostat by your ways. Thanks agian!

  2. I have a cedar creek silverback 2013 5th wheel thermostat has power to it (green light indicator on in all modes) but no response from ac,fan or furnace
    Tstat is dometic black three wire with three mod settings ac,fan and furnace
    Can anyone help on this.

    1. Hello Jamie, my name is mark. I am also having the same problem with my air, fan and heater not working. Did you ever find a solution? Love to here it if you did.

  3. hello,
    have a 2012 coachmen mirada with duel thermostats seems the front thermostat works fine
    for the kitchen main cabin area, but the thermostat in the back bedroom does not seem to
    engage in cooling or heating. my question is this when there is 2 roof top air conditioners
    does each thermostat control one of the units separate from each other, same applies to heat.
    With that said I am considering changing out the rear thermostat. any input would be appreciated.

    1. Did you ever find a resolution to your problem, Doug? I’m having the same issue with a dual-zone system.

      1. I had an issue like this with a Dometic unit, the dual zone runs on a phone wire for comm. To the total. Check the connectors on the phone jack connector at the unit. Ours were dirty and not making good contact to cut the units on.

  4. I have a RVP 8000 Series that has a remote thermostat that the green indicator light is not coming on. Were do I start.

  5. David Michelson

    If the temperature readings are not accurate in your rv, my fix worked well. After taking the thermostat base plate off of the wall, I discovered a big hole into a non ventilated area. This area vented directly through the back of the thermostat. I put tape with foam over the hole, and added spacers behind the base plate, and voila! Works perfect. Air temp of the coach can accurately be regulated since fix.

  6. My suburban 1C20-130 will not cycle off unless I actually turn it off. It continues both fan and heat if I try set it to run.

  7. I just replaced the capacitor on my Dometic AC unit. Appears to be working now. No more hot air, getting some cool air but not getting very cold air. I didn’t find any leaks in the unit.
    I lowered the temperature on the thermostat but no change in the air temperature. Could it be a faulty thermostat? Thank you.

  8. My ac unit won’t come on unless I turn thermostat off and then turn back on then works fine for couple hours or even a day but then I have to turn off again. Any suggestions

  9. Loren Pattschull


  10. Our Thermostat has power but will not automatically start furnace. We pushed the mode button to fan and it come on, back to furnace and started fine.
    Repeated same thing a few hours later

  11. William Hayward

    If I set the gas heat for 73 deg it works fine. But if I set the heat for 74 deg or above that then the heat does not shut off even if I turn the thermostat off. I can only stop the furnace but shutting off the propane supply. The air cond works fine.
    I have an “RV Comfort zc” unit controlling a Suburban SF30 FQ furnace.

  12. Dennis Fitzgerald

    Gotta be honest I’m not impressed with the domestic thermostats I’ve had in my trailer. Now the heater won’t start and it’s getting colder. Already replaced 1 thermostat with a road service charge of $500 . I’m going to talk with the dealer about replacing it with another make when I get home.

  13. I have a Montana high country 5th wheel with two air conditioners. one in bed room and one in back bunk room. it has a Dometic 3314080 thermostat. it just started letting only one unit run at a time. i can turn both on and one will run and the other want. doesn’t matter which unit i set to the lowest temp. is this the thermostat. or controller box. does anyone know

Leave a Comment

Your email address will not be published. Required fields are marked *