Coleman Mach Air Conditioner Troubleshooting Guide (6 Fixes!)

Coleman is known for its reliable and stylish Mach air conditioners, but that doesn’t make them faultless. Sometimes these units fail, thus requiring a Coleman Mach air conditioner troubleshooting guide.

A troubleshooting guide can help you fix a Coleman Mach air conditioner that won’t turn on or off, cool or heat, or one whose compressor or fan is not working.

Those six issues are going to form the basis of this troubleshooting guide. I’ll help you recognize and fix the likely causes of each case. Thus, you won’t need to call Coleman or your local HVAC expert each time your Mach AC won’t work. 

That, however, doesn’t mean that all issues are DIY troubleshootable. Some will need professional help, and I will highlight them to help you draw the line quickly.

So, let’s get into it.

Coleman Mach air conditioner troubleshooting

In a rush? Find a quick troubleshooting guide for the 6 Coleman Mach air conditioner problems below.

Quick Coleman Mach Air Conditioner Troubleshooting Guide

ProblemLikely CauseRecommended Fix
1.Coleman Mach AC Won’t Turn OnPower outage, blown-up fuse, tripped breaker, unit not plugged in, faulty wiring, non-responsive remote, or bad thermostat or capacitor Check for possible power outages and ensure the AC is plugged in. Reset the breaker if flipped off and replace the fuse if it has no continuity. Replace the remote’s batteries and call an expert to check the wiring thermostat or capacitor
2.Coleman Mach AC Won’t Turn OffDirty condenser coils, or a defective thermostat, relay board, temperature control board, or main control boardClean the condenser coils if they are dirty and replace any of the other components if they are defective
3.Coleman Mach Air Conditioner Not ColdDirty air filter or outdoor unit, wrong setting, wrong size, low refrigerant or faulty fan, thermostat, compressor, or control boardClean the air filter and outdoor unit (condenser coils and compressor) if they are dirty. Lower the thermostat setting or get a bigger AC if it’s small. Ask for expert help to fix a refrigerant leak and replace a faulty fan, thermostat, compressor, or control board
4.Coleman Mach AC Won’t Heat Power distribution, dirty filter, wrong temperature setting, frozen coils, leaky refrigerant, faulty wiring, or failed heat strip or fan Reset the breaker and replace the thermal fuse if faulty. Raise the thermostat setting, thaw out the coils if frosty, replace a failed heat strip or fan and turn to an expert to fix  faulty wiring or leaky refrigerant
5.Compressor Not Working Frost build-up, dirty coils, burnt overload, or bad thermostat, temperature control board, or compressor Thaw out the frosted coils, clean dirty coils, and replace a bad overload, thermostat, temperature control board, or compressor
6.Fan Not Working Worn-out or defective fan motor, bent fan blades, burnt thermostat or blower motor, or failing relay board, capacitor, or control boardReplace any of the components if it’s worn out, defective, bent or burnt

6 Common Mach Air Conditioner Troubleshooting Problems (Coleman Mach Air Conditioner Not Working)

Below are six common Mach air conditioner problems for troubleshooting:

See also  Fixing Your Issue: Honeywell Thermostat Not Turning On Heat

1. Coleman Mach Air Conditioner Not Turning On

A Coleman Mach air conditioner doesn’t fail to turn on unless something is wrong. While it’s often a case of the unit not getting power, it could sometimes be a component malfunction.

Here are the likely reasons why your air conditioner won’t turn on:

  • Power outage – You’re Coleman Mach won’t turn on if there’s no power. So, you have to check if there’s an outage. If not, then consider the other issues.
  • Unit not plugged in – It’s easy to forget to plug in the air con and assume that something is faulty. So, check the power cable to ensure it’s plugged in and turned on.
  • Tripped breaker – The breaker flips off during an overvoltage or power surge. That’s likely to stop the AC from turning on. 
  • Blown fuse – An overvoltage or power surge will likely prevent the air conditioner from starting. You can test it with a multimeter to determine whether it has continuity. 
  • Non-responsive remote – If the remote control doesn’t respond to your pressing, it won’t turn on the air conditioner. In most cases, the issue is exhausted batteries.
  • Faulty wiring – If there’s a problem with your electrical wiring, the air conditioner won’t turn on. That includes loose and rodent-chewed cables and broken wires. 
  • Bad thermostat – With the thermostat monitoring your AC’s temperature, its defectiveness can prevent the AC from turning on. So, you may need to troubleshoot the air conditioner thermostat.
  • Bad run capacitor – The run capacitor connects the compressor through electrical leads. If it’s bad or bent, the compressor won’t run, and the AC will not turn on. 


Confirm if you have electricity or if there’s a power outage. If it’s not the latter, ensure the unit is correctly plugged into the power socket. If it still won’t turn on, check the circuit box for the tripped breaker and reset it.

Then test the thermal fuse with a multimeter. If the fuse lacks continuity, replace it. Also, test the remote control to see if it’s working. You can replace the batteries if it has been a while (over a year).

If the unit still doesn’t turn on, talk to an expert to check for faulty wiring or a potentially bad thermostat or capacitor. 

Coleman Mach air conditioner not turning on

2. Coleman Mach Air Conditioner Won’t Turn Off

Sometimes the Coleman Mach would turn on but fail to turn off. If that’s the case, the likely causes are as follows:

  • Dirty condenser coils – If the condenser coils are filthy, they fail to dissipate heat well and force the compressor to run continuously to try and cool the unit.
  • Defective thermostat – Sometimes, the AC may turn on when the thermostat is faulty but unable to turn off as the thermostat cannot monitor the temperature changes. 
  • Defective thermistor – The thermistor also detects the temperature changes like the thermostat and will prevent the AC from turning off if it is faulty. 
  • Bad relay board – If the relay board is faulty, the compressor won’t get a consistent voltage supply, which can stop the AC from turning off. 
  • Failing temperature control board – A bad temperature control board may cut off the compressor’s voltage supply, causing the compressor to run on stop. 
  • Failed control board – The main control board also cuts off the compressor’s voltage supply when faulty, and that stops the AC from turning off. 
See also  Step-by-Step Guide: How to Replace Air Conditioner Drain Pan


Clean the condenser coils if they are dirty and replace the thermostat, thermistor, relay board, temperature control board, or main control board if faulty. 

3. Coleman Mach Air Conditioner Not Cooling

While you expect the Coleman Mach to blow cold air during the scorching summer, sometimes it doesn’t. So, why is your Coleman Mach air conditioner not blowing cold air?

The reason is likely to be one of these:

  • Dirty air filter – Once the air filter is dirt clogged, air cannot flow correctly, preventing the air conditioner from cooling. Additionally, it causes the evaporator coils to frost over, which only makes your space warmer as the unit won’t blow cold air. 
  • Dirty outdoor unit (condenser coils and compressor) – Your outdoor unit can also prevent the AC from cooling your space if dirt-clogged. In particular, the condenser coils and compressor cannot run when dirt-caked, which affects the cooling. 
  • Wrong thermostat setting – The air conditioner won’t blow cold air if the thermostat’s temperature is higher than the room temperature.
  • Wrong AC size – The AC should match the room size. If it’s too small, the air conditioner won’t cool.
  • Low refrigerant – With the refrigerant’s job being to absorb hot air, it’s unable to do so when its level drops, primarily due to leakage.
  • Broken fan – The fan has to work fine for the AC to blow cold air. If it’s broken, it’s unable to blow cold air and cool your space. 
  • A faulty thermostat, compressor, or control board – Consider the possibility of a malfunctioning thermostat, compressor, or control board. The AC won’t cool if these air con components are faulty.
See also  Step-By-Step Guide: How to Drain a Toshiba Portable Air Conditioner


Inspect the air filter and the outdoor unit (especially the condenser coils and compressor) for dirt and clean them.

Then check the thermostat setting to ensure it’s set to cool. So, you may need to lower the temperature a few degrees (lower than your room temperature).

If the air con is undersized, you may need to upgrade its size.

Call an air-con expert to check and fix a low coolant level (refrigerant leak), and replace a broken fan or faulty thermostat, compressor, or control board.

4. Coleman Mach Air Conditioner Not Heating

Your Coleman Mach AC may fail to heat during the cold season, and often, the reason is one of these:

  • Power disruption – A blown-up fuse or a flipped circuit breaker is likely to disrupt the AC’s power supply and stop it from heating. 
  • Dirty filter – The filter cannot allow warm air to pass through if it’s dirty. 
  • Wrong thermostat setting – If the thermostat setting is lower than the room temperature, the air conditioner won’t heat.
  • Frozen coils – Frozen coils also make it hard for the AC to blow hot air. Once frozen, the coils prevent air from blowing over them.
  • Leaky refrigerant – A low refrigerant also makes it difficult for the air conditioner to absorb cold air and blow hot air. 
  • Faulty wiring – If there’s an issue with the wiring, the air conditioner won’t get enough power to heat your space. 
  • Failed heat slip – With the heat slip’s job to heat, the air conditioner cannot produce and spread hot/warm air when it fails.
  • Faulty fan – The air conditioner will also find it difficult to cool if the fan is faulty. A defective fan is unable to blow cold air properly.


Reset a flipped breaker and replace a blown-up fuse (test it for continuity to determine if it’s faulty). Clean the air filter if dirt is clogged, and raise the thermostat temperature setting if it’s lower.

Thaw out the condenser coils if frozen and replace a faulty heat slip. Ask an expert to help fix faulty wiring or leaky refrigerant.

Coleman Mach air conditioner not cooling

5. Coleman Mach Air Conditioner Compressor Not Working

As shared earlier, one of the reasons your air conditioner won’t blow cold is a bad compressor. But what causes the compressor not to work?

Well, it’s most likely to be one of the following:

  • Frost build-up – If there’s excessive frosting over the coils, which is often the case due to low refrigerant, the compressor won’t work.
  • Dirty coils – If the evaporator /condenser coils are filthy, the compressor will struggle to power up and run. 
  • Burnt overload – The overload’s job is to save the compressor from overheating. If it overheats and burns out on its behalf, but once it happens, the compressor won’t work. 
  • Bad thermostat, compressor, or temperature control board – If the thermostat or temperature control board is faulty, the compressor won’t work. But still, the problem could be the compressor itself which is defective.


The evaporator coils need thawing out if they are frosted, and you may need an expert’s help. Meanwhile, clean the coils if they are dirty and replace the overload or thermostat if they lack continuity.  

6. Coleman Mach Air Conditioner Fan Not Working

Lastly, if the air conditioners fan is not working, it’s likely because of one of these issues:

  • Worn-out or defective fan motor – If the fan motor is worn out or faulty, the fan system won’t be able to blow any air. 
  • Bent fan blades – The fan will also find it hard to blow air if its blades are bent. 
  • Burnt thermostat or blower motor – If either the thermostat or the blower motor is burnt, which may happen due to an overvoltage, the fan won’t turn. 
  • Failing relay board capacitor, or control board – The relay board, capacitor, and main control board must be operational for the fan to run. 


Consider replacing the worn-out, defective, or burnt-out component. 

How to Reset Coleman Mach Air Conditioner?

Is your Coleman Mach air conditioner not working, and you cannot fit it? Perhaps you should try resetting it.

Here’s how to perform a quick reset:

  • Turn off the thermostat
  • Locate the fuse and take it out for about 5 minutes
  • Put the fuse back on and wait for another 5 minutes
  • Turn the thermostat on to complete the reset

Closing Thought

Above is a Coleman Mach air conditioner troubleshooting guide to fix a non-working or malfunctioning Coleman Mach AC. Ideally, it’s advisable to try troubleshooting the AC before calling a Coleman dealer or a local HVAC expert.

As you’ll realize, most of the issues are DIY troubleshootable, which is what this guide encourages.