/ / / Coleman Mach Thermostat Troubleshooting: 4 Common Issues Addressed

Coleman Mach Thermostat Troubleshooting: 4 Common Issues Addressed

As the seasons change and temperatures fluctuate, nothing is more frustrating than a malfunctioning thermostat, leaving you shivering in the cold. But fear not, as this Coleman Mach thermostat troubleshooting guide is here to save the day!

Even the best technology can sometimes encounter issues, and that’s where troubleshooting comes in. Read on to explore the ins and outs and common issues and also learn some bad thermostat indications at the end.

So, let’s discover!

A Glimpse of Coleman Mach RV Thermostat

Coleman, a reputable company in the outdoor industry known for producing dependable camping gear, receives numerous awards every year for several tents in their lineup.

  • As an international company that produces camping gear and RV accessories, the thermostat is one of their widely-known product.
  • The Coleman Mach is an analog thermostat that requires manual adjustments by the user.
  • However, it lacks a programmed feature to respond automatically to changes in temperature.

Here’s more information:

Coleman Mach is an analog thermostat that requires manual adjustments by the user

Less Expensive

It is common practice to install a manual thermostat in a recreational vehicle. Due to their more straightforward design, these thermostats are less expensive and less likely to malfunction.

  • They serve the primary purpose of controlling the temperature in your HVAC system in a straightforward manner.
  • Not needed adjustment configurations or settings

Flat Coil Feature

Despite being a manual device, it is more technologically advanced compared to the original mechanical thermostat. It used a flat coil to measure temperature and only had a few wires to activate the fan motor.

Inside the Coleman Mach

Here’s the insight:

  • The Coleman Mach thermostat features a modern circuit board and updated electrical components.
  • The entire heating, ventilation, and AC unit system relies on capacitors and electronic circuitry.
  • The circuit breaker board is protected by a fuse, which can be replaced if a fuse is blown.

Common Issues Related to Coleman Mach Thermostat and Troubleshooting Them

RV owners frequently choose Coleman Mach thermostats because of their user-friendliness and dependable performance. Nevertheless, like any electronic device, they can encounter some occasional issues. Here are some typical problems with their solutions:

Common Issues Related to Coleman Mach Thermostat and Troubleshooting Them

1. Unresponsive Thermostat

The most common complaint is that the thermostat suddenly stops responding:

  • Power: It indicates that the defective thermostat is not receiving sufficient power in the circuit board to function correctly.
  • Batteries: If the device is battery-operated, the first step is ensuring the batteries are still functional. Replacing the dead batteries, in most cases, is enough to revive it.
  • Connections: If it is hardwired into a wall outlet, look over the wiring and connectors to ensure they are not frayed, corroded, scraped, or otherwise disconnected.
  • Broke thermostat: The device might need repairs or replacement if there is evidence of a broken thermostat or corroded wiring.
Follow these guidelines:

  • Use a voltmeter to ensure that the mains-operated device receives the appropriate power at the correct voltage.
  • If the voltage is inconsistent or incorrect, it may indicate a problem with the outlet that needs to be resolved.
  • To avoid further complications, using a different outlet is the best course of action.
  • If a voltmeter is unavailable, test the outlets in your home by inserting a tiny bulb into one and observing whether the light turns on.
  • If the problem persists across multiple outlets, the batteries or generator may be the source of the issue.

2. Non-Operational Thermostat

If you are experiencing problems with your room temperature, either the thermostat is malfunctioning or requires adjustment:

  • Before taking any further steps, please ensure the thermostat is properly set.
  • If the current setting matches the desired temperature, it may be necessary to adjust the thermostat for it to activate.
  • If you need help understanding which setting to use or frequently forget to make necessary changes, opt for an auto setting.

The location of the thermostat can also impact its accuracy.

  • Placing it in the coldest part of the room will cause it to always report a colder temperature than the actual temperature.
  • Similarly, if it is located in an area directly exposed to sunlight, it may indicate a higher temperature than the actual room temperature.
  • It is recommended to place the thermostat in a location with the same temperature as the surrounding area.

3. Requiring A Reset

Suppose you are experiencing issues with your Coleman Match thermostat and have tried troubleshooting steps like checking the batteries and ensuring that the thermostat is properly connected to your HVAC system. In that case, a reset may be necessary.


Here are the steps to reset the Coleman Match thermostat:

  • First, ensure no electricity is running through the thermostat by removing the fuse.
  • Next, turn off the device and leave it idle for at least five minutes.
  • Once it is done, replace the fuse and turn on the device.
  • If issues persist, consider replacing the fuse to see if it resolves the problem.

4. Blank Screen

Diagnosing and resolving issues when you have a blank screen is very challenging. The Coleman Mach Thermostat is a popular device for controlling air conditioners and furnaces in recreational vehicles (RVs).

consider replacing and resetting the power supply fuse to check the problem

If you are experiencing a blank screen issue on your Coleman Mach Thermostat, there are several possible causes and solutions you can try.


Here’s what you need to do:

  • First, follow the instructions in Part 1 for troubleshooting a non-responsive thermostat.
  • If this approach is unsuccessful, consider replacing and resetting the power supply fuse.
  • Further troubleshooting may be necessary if the problem persists after attempting these steps. This may include checking internal hardware components or seeking assistance.

5. Check Batteries

Even though the Coleman Mach thermostat is manual, it still requires two AA batteries due to its utilization of state-of-the-art components such as capacitors and circuitry. Making it convenient and easy to use.

To troubleshoot any issues, we recommend starting with the easiest solution by verifying that both batteries have reached 100% capacity and providing at least 1.5 V of electricity. Even one with a dead power could cause problems, so it is important to check and replace both if necessary.


Here’s what will get things done:

  • You can easily change out the batteries, as they are located on top of the thermostat and concealed by the top plate.
  • To access them, gently grasp the side of the plate and pull it towards you to remove the lid.
  • No cables or obstructions are holding the cover plate in place. After removing the cover, store it nearby but out of the way to avoid misplacing or crushing it.

6. Check Fuse

By removing the protective cover, you can inspect the motherboard and capacitors. Additionally, a 2 amp fuse in the bottom left corner will keep the thermostat safe in case of a power surge. This fuse may be the root cause of your issue, so it’s important to check it as part of your troubleshooting process.

By removing the protective cover, you can inspect the motherboard and capacitors

Follow these instructions:


  • To check if the fuse has blown, inspect the glass vial and look for severed internal wire or dark stains on the glass
  • Use a flashlight to help you see clearly.
  • If the fuse is blown or not intact, replace it with a new one, which can be purchased at any hardware or RV store.
  • After swapping out the old fuse for a new one, the thermostat problem should be resolved.

However, if the fuse keeps blowing despite your efforts to replace it, you may have a more serious electrical issue than just your thermostat. Keep on reading to find more info.

7. RV Maintenance for Blowing Cold Air Conditioner

The Coleman Mach is a great thermostat as it can power both your heater and air conditioner, although most thermostats also have this capability. The relay’s 120V power source can signal your air conditioner to activate the compressor.

However, since the low-voltage thermostat, it cannot directly power 120V like a switch can. Activating a relay in your air conditioner produces cold air. If your ac doesn’t turn on, ensure the thermostat is set to the correct settings.


Here’s what we recommend:

  • Switch to the automatic blower fan mode. This way, the fan will switch on automatically when the air conditioner is activated.
  • If the switch is turned to the “on” position, the fan will constantly operate, even if the air conditioner is not in use.
  • Next, slide the “system” button to “off” and then back to “cool” air to test the thermostat’s functionality.
  • Sometimes, the slide switch needs to be in the correct position, even if it appears to be. Turning it off and then back on should do the trick.

8. Keep Furnace in Good Condition

A furnace for a heating system operates differently than an air conditioner. Unlike an air conditioner, you can’t use standard 120-volt electricity with a furnace. Instead, the device and blower motor is powered by propane and 12-volt electricity from your battery.

Since there’s no need for a relay to activate 120V electricity, your thermostat can be controlled with less effort.


To fix the furnace, follow a similar process to fixing the air conditioner.

  • First, select “heat” on the thermostat and switch the fan to automatic mode. This ensures that the fan only turns on when the heater is in use instead of running constantly, regardless of whether the furnace is on or off.
  • If there are issues with the thermostat, try turning it off and then on again in the “heat” setting. It should fix the problem.

9. Wire Properly

check the wires to ensure they're not frayed and all bolts are tightly fastened

The RV’s wiring system may be problematic due to the thermostat’s connection. Six wires with different colors come out of the Coleman Mach, each with a specific purpose. The air conditioning, for example, depends on a unique blue cable.

As you travel with your RV, a loose wire can become disconnected and cause issues.


You need to perform a few checks to ensure the proper functioning of your thermostat.

  • First, check the wires to ensure they’re not frayed and all bolts are tightly fastened.
  • Loose connections or slack in the wires are unacceptable.
  • Next, inspect the thermostat’s circuit board to see if any wires are loose or disconnected.
  • Although less likely, a loose wire can still cause a tripped breaker; therefore, you need to do a thorough inspection.

10. Checking for Bad Thermostat

Switching to programmable RV thermostats is a smart choice, even if your current one works fine

If the previously mentioned troubleshooting steps fail to fix the issue, you may have a faulty thermostat. The numerous electrical components and sliding switches the thermostat utilizes increase the potential for malfunction.


Here’s what needs to be done:

  • Upgrading to a new thermostat is a simple and cost-effective solution, with prices ranging from $75 to $100.
  • When replacing the thermostat, it’s best to do so wire-by-wire. Although the wires may be color-coded, the RV’s wiring system may not always match the color of the wires.
  • The wire-by-wire method minimizes the risk of damaging your RV by accidentally connecting the wrong wire.

For more insights, check out this video.

How To Identify A Bad Thermostat?

There are a few indications to your RV thermostat not functioning properly. Here are some of the most common signs of a bad RV thermostat:

How To Identify A Bad Thermostat work

The Furnace or AC Not Activating

If the RV’s thermostat is malfunctioning or displaying incorrect readings, it may prevent the heating and cooling system from being activated according to the desired settings on the thermostat panel. This is due to the thermostat’s sensitivity to temperature settings.

While the temperature setting is incorrect, a failing RV thermostat could be the underlying issue.

Short-Cycling Problems

The camper or RV’s heating or air conditioning system may fail to run continuously:

  • This can cause the system to shut off prematurely when attempting to warm or cool the space.
  • While retrying may result in the thermostat providing accurate readings and a more comfortable environment, the same issue can occur again.

Communication Failure

There are things that you should know about communication failure:

  • When you adjust the thermostat, you should hear a distinct clicking sound as the fan or heater turns on
  • After that, the clicking noise should stop, indicating proper communication between it and the heating/cooling system.
  • If the clicking does not occur or occurs, but nothing happens, it may be necessary to replace the RV thermostat immediately
  • Ignoring the issue will likely result in further problems.

Programmed Memory and Thermostat Setting Issues

It can be disheartening when the thermostat, which used to accept your desired settings, now appears to be malfunctioning. As a first step, try adjusting the thermostat’s settings.

However, if the changes do not take effect or disappear altogether, it’s possible that a more significant problem, such as a battery malfunction, is at play.

Recommended Coleman RV Thermostat

The Coleman 83303862 Digital Thermostat provides an easy-to-use and efficient solution for controlling your heating and cooling systems.

  • It features a large and easy-to-read digital display that shows the current temperature and allows you to adjust the settings effortlessly.
  • This thermostat is compatible with most heating and cooling systems, including gas, oil, electric, and heat pump systems.
  • Its programmable settings allow you to set temperatures for different times of the day, enabling you to stay comfortable while saving energy and reducing costs.

Upgrading Your Thermostat

Switching to programmable RV thermostats is a smart choice, even if your current one works fine:

  • RV manufacturers often use analog ones to save money, but they are unreliable and can be off by 10 degrees Fahrenheit. This causes the need for constant temperature adjustments to stay comfortable.
  • There is no “off” option with analog thermostats, so you have to pull the fuse to turn off the furnace.
  • Upgrading to a digital non-programmed device can provide more accurate settings, but you won’t be able to set specific temperatures for certain times.
analog vs digital thermostat

Choose Programmable Thermostat

Choosing a programmable thermostat allows you to set and forget your temperature routine, which is perfect for long-term RV owners. During the harsh season, you can lower the temperature at night to blow cold air in the RV and raise it before waking up.

While in hot air months, you can activate the AC unit to return to a cooler RV.

Check Your RV Configuration Before Buying

The best-programmed thermostat depends on your current setup. There are some important things to keep in mind:

  • Coleman and Dometic thermostats are a good purchase as replacements, so research before buying a $100 thermostat that won’t work with your system.
  • Some thermostats only regulate heat, while others control heat and AC, so RV configuration matters.
  • Upgrading from an analog thermostat to a programmable or non-programmable one can make a significant difference in keeping your RV at a consistent temperature.

Coleman Mach Thermostat Troubleshooting – FAQ

How do I reset my Coleman thermostat?

To reset the Coleman thermostat, follow these steps: Turn off the thermostat, remove the fuse, and wait 5 minutes. After 5 minutes, replace the fuse and wait for another 5 minutes. Finally, turn the thermostat back on to complete the reset process.

How do I know if my RV thermostat is bad?

If your RV thermostat is bad, check these three signs. First, your RV thermostat is unresponsive. Second, your RV thermostat setting doesn’t align with the actual temperature. At last, the heat or A/C won’t switch off or on.

Does my Coleman-Mach have heat?

Yes! Your Coleman-Mach does have heat. The HP2 high-performance heat pump offers an inexpensive, electric heat source and a high-performance air conditioner in one sleek package.

How do I pair my Coleman-Mach thermostat?

To pair your Coleman-Mach thermostat, turn on your Coleman-Mach AC unit and press the “Mode” button until you see “PAIR” displayed on the screen. Then, press and hold the “PAIR” button until the display changes to “PAIRING”. Within 60 seconds, press and hold the “PAIR” button on the control box unit until the LED on the control box starts flashing.

Can I replace my RV thermostat with any thermostat?

No, you can not replace your RV thermostat with any thermostat because RVs typically do not provide sufficient power to operate a standard home thermostat since these thermostats require more than the 12 volts DC typically provided in RVs.


Taking the time to troubleshoot and resolve any issues with your Coleman Mach Thermostat is essential for ensuring optimal convenience. Following the steps outlined in this guide, you can address any problems with your device and avoid unnecessary discomfort in your RV.

What problems with the Coleman Mach thermostat did you have, and how do you solve them? Provide us with your feedback in the comment section below!

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