/ / / Coleman Mach RV Air Conditioner Troubleshooting: 6 Recommended Fixes

Coleman Mach RV Air Conditioner Troubleshooting: 6 Recommended Fixes

Most campers come with Coleman ACs. While the machines are affordable and reliable they are not prone to problems. But don’t worry!

This Coleman Mach RV Air Conditioner Troubleshooting pro guide addresses problems such as why won’t the AC turn on or off. Why does it not cool or heat properly? Issues with the thermostat setting and their solutions.

With our in-depth research, we also have solutions to uncommon problems with compressors that are quite difficult to understand. So bring out the tools and start reading.

Why the Troubleshooting? Importance Discussed!

Coleman Mach ACs units are produced by the company with the same name.

  • These air conditioners are renowned for being dependable, effective, and long-lasting.
  • They are made to provide excellent cooling even in humid and hot climates.
  • You can select from a variety of models and sizes to fit different your campers.

Although, do not forget proper timely maintenance. There are countless problems you can avoid if you are well-versed in fixing these. The following issues and more may impact a unit’s overall efficiency and lifetime:

  • Poor cooling performance
  • Leaks
  • Electrical faults.

Coleman Mach AC Troubleshooting Guide: Causes and Solutions

Frequent servicing can help in preventing the rise of more critical problems that could require major repairs. Troubleshooting can also assist in locating any safety issues that can compromise the environment or the RV’s passengers. For example electrical troubles or refrigerant leakage.

This is why the following section will address common issues, their causes, and dedicated solution.

1. Coleman Mach AC Not Turning On

Believe it or not, but like other brands, it is possible that the Coleman Mach air conditioner won’t switch on. To make it go back to functioning properly here is what you need to know.

Likely Cause

First, let’s determine the root of the trouble. If the Coleman RV air conditioner does not switch on the problem could lie with one of the following:

  1. Non-Responsive Remote
  2. Power outage.
  3. Blown fuse.
  4. Faulty wiring.
  5. Tripped breaker.
  6. The unit is not plugged in.
  7. Bad thermostat.
  8. Capacitor malfunctioning.
Recommended Fix

Doing the following will most likely fix this issue:

  • Change the batteries in the remote.
  • Verify that the AC is plugged in and keep an eye out for any power outages.
  • In case there is no continuity, replace the fuse.
  • If the circuit breaker was turned off, try resetting it.
  • Call an expert to check the electrical wiring.
  • Involve an electrician in case of a bad thermostat or capacitor as well.

2. Coleman Mach AC Not Turning Off

This issue does not happen often. Although in the likely scenario where you are unable to switch off the Coleman Mach Air Conditioning unit, read below.

Likely Cause

Let’s learn which component can cause this to happen:

  1. Dirty condenser coils.
  2. Defective thermostat.
  3. Faulty Relay board.
  4. Flawed control board.
  5. Malfunctioning Main control board.
Recommended Fix

To successfully switch off your air conditioner here is what needs to be done:

  • If the condenser coils are dusty, clean them.
  • If any of the other parts are damaged beyond repair or not functioning correctly, replace them.

3. Air Conditioner Not Blowing Cooling Air

There could be many reasons why your RV air conditioner does not blow cold air as it should. Scroll down to see as we get to the bottom of the ac unit not throwing cool air.

Likely Cause

Owners of the Coleman Mach air conditioner have regarded one of the following components responsible:

  1. Dirty air filter
  2. Wrong setting
  3. AC with less BTU
  4. Low refrigerant
  5. Issues with the fan motor
  6. Faulty Thermostat
  7. Malfuntion in Compressor
  8. Faulty Control board
Recommended Fix

Take the actions below and your RV air conditioner will blow cold air and chill indoors in no time.

  • Clean the dirty filter and outdoor unit.
  • Lower the thermostat setting.
  • Get a bigger AC if it’s small.
  • Replace the faulty fan
  • Check the Thermostat. Replace if needed.
  • You may need to change the compressor.
  • Get a new control board.
  • Call an expert to inspect for refrigerant leaks.

4. AC Not Blowing Heat

If you invest in a thermostat model that can both heat and cool, it is rather disappointing when it fails in harsh weather. Good thing Coleman products are fixable. Let’s learn more.

Likely Cause

To get your unit to start blowing hot air normally inspect the following:

  1. Issues with Power distribution
  2. Unclean filter
  3. Incorrect temperature setting
  4. Frozen coils.
  5. Leaky refrigerant
  6. Faults in the wiring
  7. Problems with heat strip or fan
Recommended Fix

We are confident that by taking the measures mentioned here you will be able to fix the hot air setting:

  • Reset the circuit breaker
  • Check if the thermal fuse needs replacement.
  • Modify the thermostat setting.
  • Clear frost build-up from the coils.
  • Changing the heat strip or fan will help.
  • Issues with wiring should be handled by a professional.

5. Compressor Not Working Properly

If the Coleman Mach air conditioner is having issues with its compressor unit, we have some troubleshooting steps you can do to overcome that. Have a look at the causes and solutions.

Likely Cause

Malfunctioning air conditioner compressors can have problems due to:

  1. Frost collected.
  2. Dust and dirt in coils
  3. Burnt overload Thermostat
  4. Temperature control board
  5. Fault in Compressor
Recommended Fix

The experts advise that doing the following will help the compressor and the system:

  • Brush out the frosted coils.
  • Clean dusty coils.
  • Replace the thermostat to fix overload.
  • Change the temperature control panel
  • Upgrade the compressor itself.

6. Fan Not Working Properly

Fan and its motor can fall victim to damage or underperform due to few components of the AC unit. Let’s learn how to diagnose and fix it.

Likely Cause

  1. Faulty or damaged fan motor.
  2. Worn-out fan blades.
  3. Burnt thermostat.
  4. Blower motor.
  5. Malfunction with the relay board.
  6. Problems with the capacitor.
  7. Flawed control board.
Recommended Fix

The solution to this is pretty straightforward and simple.

  • Replace the air conditioner fan motor.
  • Get a new thermostat if it is burnt.
  • Change the control box to a new one if damaged.
  • Replace the capacitor if it is burnt.

RV Thermostat Setting

The Coleman Mach thermostat is not programmable. It operates on an analog system. This signifies that there is no mechanism to change the set temperature automatically and that all settings must be adjusted manually by the user.

Although it makes them simple, and easy to operate. They are however more likely to break but still considered very high-tech. More on this is below.

Temperature and Hot Air

It is possible to change the room temperature while using a Coleman Mach, however, the actual temperature is not indicated on the display.

  • Please be aware that the temperature set on the thermostat refers to the desired temperature.
  • You will not be able to determine the difference between the set temperature and, the actual temperature within the camper.

This might make it challenging to identify issues. So how can you fix it? We’ll let you know.


Perform the following and the settings will be fixed after you are finished.

  • If you want the HVAC system to provide heat, verify that the thermostat is set higher than the RV’s interior temperature. Since this thermostat does not provide room temperature readings, this may require a guess.
  • To be certain, raise the temperature setting to the highest point. This should turn on the heating, throw warm air and activate the fan motor.
  • If you want cold air from your air conditioner, adjust the temperature bar to the lowest setting, as you won’t be able to see the room temperature. This will force the air conditioner to turn on and blow cold air.
  • If you have the correct settings and are still not getting the desired heat or cold air, continue with further troubleshooting.

For more insights, check out this video.

Other Reasons Why Coleman Mach RV AC Won’t Work

Let’s talk about the point where you have done every recommended troubleshooting procedure but your air conditioner is not willing to work.

Remember that these are complicated machines. A lot goes into it so there are other remedies you can do that will hopefully fix them. Let’s dive into the reasons:

1. AC Unit Relay Defective

When troubleshooting AC units that are not turning on, it is important to consider the relay as a potential culprit. The relay:

  • Serves as a switch that provides the AC unit with 120V power to turn on.
  • May prevent power from reaching the AC unit even if the thermostat is sending the signal to turn on.
  • May need to be replaced if found to be defective, to restore the normal functioning of the AC unit.

2. Defective Thermostat

One possible reason for an air conditioner not working could be an issue with the thermostat. If any of the components or capacitors in the thermostat are damaged, it could prevent the air conditioner from functioning properly. Symptoms of a faulty thermostat may include:

  • No power to the thermostat.
  • Unresponsive buttons or controls.
  • Incorrect temperature readings.

Note: It’s essential to remember that an air conditioner’s failure might also be caused by other things, such as a clogged air filter, low refrigerant levels, or damaged wiring.

To ensure safety and stop future harm to the air conditioner, it is preferable to have a professional technician diagnose and fix the problem if you think your thermostat is faulty.

3. Inspect the Circuit Breaker

There may be other causes for the Coleman RV air conditioner malfunction than a defective thermostat. When electrical power to the air conditioner is cut off, a tripped circuit breaker is oftentimes the cause of the issue. To confirm if the circuit breaker has tripped:

  • You will have to locate the electrical panel. The air conditioner breaker is typically the largest one in the panel since the air conditioner requires the most power to operate.
  • Check the labeled breaker for the air conditioning unit.
  • See if the electrical power to the air conditioner is disconnected. Sometimes a breaker may appear tripped but is only partially disconnected, which can cause the air conditioner not to work properly.

Reset the breaker if it looks to be tripped. It is advisable to have a professional technician diagnose and fix the issue if resetting the breaker does not fix it.

How to Operate Coleman RV Air Conditioners

The Coleman-Mach RV air conditioner operates from the control panel located in the ceiling assembly. It has three controls which are:

  • Selector switch: Allows you to choose between fan mode, cool mode, and heat mode, depending on your desired preference.
  • The thermostat (temperature control): It adjusts the temperature to your desired level.
  • The louvers: It controls the direction of the airflow. It helps to adjust the angle and direction of the air coming from the air conditioner.

Read below to learn what is possible with these controls.

Use it for Cooling

In order to make your drop a few degrees and cool the interior of the RV, you will need to follow these steps.

  1. Depending on your preferred level of cooling, move the selector switch to either the “LOW COOL” or “HIGH COOL” position.
  2. When the air entering the air conditioner gets warmer than the setting you’ve chosen, the thermostat will start the compressor.
  3. The compressor will continue to maintain that particular temperature by turning it off and on. Change the setting to disrupt this cycle when needed.
  4. Angle the louvers in the direction of where you want the air to flow. These can be adjusted to flow the air up, down, left, or right.

Short Cycling

Short Cycling is a term used to indicate how frequently air conditioners or heaters cycle on and off. The AC compressor circulates refrigerant under high pressure. This indicates that it will take two to three minutes after turning off for the high pressure to subside.

  • Caution: Short cycle, or starting the compressor before the pressures are equal, might result in the overload or circuit breaker tripping, potentially damaging the device.
  • Preventing it: Wait two to three minutes before attempting to restart the A/C compressor.

Use it for Heating

Follow these steps to heat the RV trailer:

  1. Set the “LOW HEAT” position on the selector switch. This will turn on the heater’s low-speed fan and increase its heat output.
  2. Adjust the required temperature by using the thermostat (temperature control) switch. The compressor is able to detect room temperature. It automatically maintains the heating by changing the on and off position when the temperature fluctuates from the desired level.
  3. Now angle the louvers in the direction where you wish the air to flow. By opening or shutting it, you may somewhat modify the temperature of the discharge air.

Use it for Just Air Circulation

To control the airflow of your RV’s air conditioner, follow these steps:

  • To pick the preferred fan speed, use the selection switch.
    • LOW FAN: for minimal airflow.
    • HIGH FAN: for the most airflow.
  • The louver’s position will depend upon where you want the air to flow.
  • Further, manipulate the temperature by opening or shutting the louvers. This will help control the emission of air.

Resetting Coleman Mach Air Conditioner: Steps

For friends who are unfamiliar with how to reset the thermostat’s model 9630-3361. Don’t worry instead please follow the steps below:

  1. Firstly, turn the thermostat off.
  2. Then, locate the fuse for the thermostat and remove it.
  3. You will need to wait for 5 minutes.
  4. After waiting, re-insert the fuse.
  5. Wait for another 5 minutes.
  6. Turn on the thermostat.
  7. The air conditioner is now reset and should be operational.

Coleman Mach RV Air Conditioner Troubleshooting – FAQ

How do I reset my Coleman Mach air conditioner?

To reset the Coleman Mach air conditioner: Turn the thermostat off then pull the fuse. Wait 5 minutes then reinsert the fuse. Wait for 5 minutes again then turn it on.

Why is my Coleman AC not blowing cold air?

Coleman AC not blowing cold air could be because of a malfunction in the compressor, a clogged air filter, or a faulty thermostat. Have an expert take a look to restore proper cooling.

Where is the reset button on a Coleman air conditioner?

The reset button on a Coleman air conditioner is next to the blower on your left. It can be found between the blue and grey wire. It is also known as a limit switch.

Why does my Coleman Mach AC click but won’t turn on?

Coleman Mach AC clicks and won’t turn usually because the relay incorrectly is turning on and off. The issue may arise due to a loose wire or a damaged relay. Consult an expert to take a look.

How do I know if my RV AC compressor is working?

To know if your RV AC compressor is working, turn the AC on and set it to the highest cold setting. If the chilly air comes out your compressor is alright.


Let’s review what we learned. Coleman Mach produces excellent ACs. Although sometimes it won’t chill or heat the room as your desire. The reason can be dirty condenser coils, a flawed thermostat, a faulty relay board, or a defective control board.

Try cleaning the interior of the unit, checking for loose wires, resetting the furnace, and repairing or replacing the damaged parts. If you are still unsure, trust an expert to do the fix.

What hurdles did you face to get the Coleman Mach air conditioner to work and are you now able to diagnose the issue? Let us know in the comments section!

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