AC Troubleshooting: Coleman Mach Air Conditioner Not Cooling

Almost every RV and trailer comes with some sort of AC unit that helps keep you cool during hot days and nights. Unfortunately, these units do not always last for years and years. When they break down, it is time to see if they can be repaired or if they need replacing.

When your Coleman Mach Air AC is not working, it could be something as simple as a tig blocking a fan from spinning. Or it could be something major like a failed capacitor. Either way, you have to do some diagnostic work to find out the source of the problem.

To learn more about troubleshooting your Coleman Mach AC unit, just continue to read our article. it has the information you need to know about so you can solve your AC issues a lot faster and hopefully a lot cheaper. Take a few minutes to see how helpful this information is to you.

Coleman Mach RV Air Conditioner Not Blowing Cold Air

Coleman Mach RV Air Conditioner Not Blowing Cold Air

There are always several sources for this problem. Knowing which one it is and finding it is the real issue. The first thing to do is check the Freon level. If it is low, the unit should not be blowing any cool air.

The next places to look will involve knowing how to read a volt or multi-meter as you need to check the thermostat and the capacitors. If they have failed or not getting power, then your AC will not pump out cool air.

Another place to check would be the fan. If it is jammed the AC unit will not work. You may have to clean the fans as well. While cleaning, look for any obstructions that are hindering their working at normal levels.

Finally, check the compressor to see if it is dirty. If so, a good cleaning should get it up and running and the cool air flowing again. If there is something wrong with the mechanics of the compressor, then you would need an AC tech to handle the replacement and diagnosis.

Replacing the thermostat or capacitor when they have gone bad is about your only repair option for those parts. Some simpler sources would be a low battery or a loose wire that makes the thermostat fail to work. Make sure to check those sources out before moving on to tougher repairs.

Coleman Mach AC Compressor Not Working

The cause of this could be that the compressor is failing and in need of repair. But before going t that solution and repair, it is best to check the fins and the coils. If they are dirty, the compressor can overheat and shut down on you.

The solution to this source would be to clean those coils and fins as best as you can. While you are checking these possibilities, you should also check to see if there is ice or frost build-up. If there is, then you may be low on Freon.

The solution to this issue is to have the compressor recharged. Don’t forget to look for water leaks, loose bolts, and broken gaskets. These are minor issues that can have a big influence on how your air conditioner works.

A burned-out compressor or a leak somewhere in the system requires a professional technician to handle the repair. It is also best to let professionals handle the recharging as they have the equipment to do the task right.

Coleman Air Conditioner Fan Not Working


There are a couple of ways to diagnose this problem. If the fan does not change speeds and operate son low no matter where you set it or if the lights dim as the air conditioner works, then you will have a problem with the fan motor or capacitor.

Both parts may be going bad and are giving you a warning that they need to be replaced. Use your nose while checking the fan out. If you smell something burning, then a bearing has burned out or a wire has done that.

The solution to those two problems is simple. Just find a fan replacement and take the old one out. Also, check for any obstructions that might be blocking the fan blades from spinning. It doesn’t take much to stop them from working. Give the fan and the area a good cleaning to be on the safe side.

A final option to try is to use the multimeter and see if power is getting to the fan. This opens up another can of worms and if you are not comfortable working with electrical things, leave it to the professionals to work on.

AC Not Blowing Hard

This is the result of a bad fan motor or a faulty or failing capacitor. These two parts are responsible for the strength of the airflow and if they are going bad, then you will not get strong flowing cool air.

The fix is the same as mentioned above and you should know how to use a multi-meter to help you eliminate simple issues. When you find out which part has gone bad, you will have to replace the parts. They are not hard to replace and with some handyman talent, you should be able to do it yourself.

Replacing the capacitor means you need to write down and take with you the required voltage as well as the model and serial numbers for the part. This will make finding a new one easier.

Whether you go to a brick-and-mortar store or shop online is up to you. Make sure the part you order is of top quality and can get to you quickly.

Coleman Mach AC Won't Turn On


Start with the simple and easy to reach sources first. Check to see if your batteries are fully charged or if someone accidentally unplugged your unit from shore power. It can happen especially when kids are playing nearby.

From there, move on to the fuse box and check to see if all the fuses related to the AC unit are intact and have not blown. While you are at it, check the circuit breaker to see if it tripped. If neither location produces any results, then move on to the wires.

A bad connection, loose wire, or even corrosion can stop your AC unit from working. Also, look at the control panel to see if it failed on you. Once you have checked these possible sources, you can move on to some of the issues we have already discussed.

First, check the thermostat to see if it is working properly or not. Then move on to the capacitor if the thermostat is okay. If neither is working then replacement is your only option.

Finally, check for dirty components or low Freon levels to eliminate them as possible suspects. In most cases, you can do the repair work yourself. But if it is the control panel, you should leave it up to a technician to handle the replacement.

Coleman Mach is Not Heating

There will be common parts between the AC and the heating side of this unit. The first thing to do is to go over certain electrical parts that control the power flow. Check the wires to make sure they are not loose. frayed, or corroded.

Then you can check the heating strip to see if it is working properly. Use a multi-meter to check to see if there are any electrical problems or to see if the strip has failed. There are times when it will fail but it is easy to get a replacement heat strip.

Also, you will need to check the thermostat to see if it is functioning right as well as the capacitor. Plus, do not leave out the control panel. There could be a problem with it and in each case, a replacement will be your only option.

Also, check the manual and look for the T-Stat section. The problem can be in there or with the furnace itself. If you are not handy in this type of diagnostic work, then call in a technician who already knows the data and can pinpoint the source quicker than you can.

Coleman Mach Freeze Sensor Location


Page 14 of the manual tells you where the evaporator freeze sensor is located. It starts from the back of the control box and you need to follow the wires until you get to the sensor.

The sensor is placed near the bottom center of the evaporator fins and between those fins and the bottom two tubes. It may be difficult to replace this sensor as you have to be careful how you move the sensor.

The sensor is inserted into position until it contacts the staggered tube directly in the back of the insertion point. Once you get that contact completed, you have to raise the exposed part of the sensor to a 45-degree angle.

To work properly, the sensor has to be 100% embedded into the evaporator. All this work is done before you connect the sensor to the control box terminals. It is not hard to connect the wires as the terminals are identified with the word ‘FREEZE’.

You do have to be careful of getting a shock. To prevent that from happening make sure the white wire is connected to neutral and the ground wire is connected to the grounding lug.

Coleman Mach Freeze Sensor Test

We found no real test that you can use to see if the freeze sensor has gone bad or not. You can check the control box to see if it is working right. If the control box has problems most likely you will have a problem with all the components connected to it.

Or you can try to touch the probes of your multi-meter to the terminals connected to the freeze sensor. This will let you know if there is any power getting to this device. But instead of fooling with it yourself, it would be a better choice to let a professional technician handle any testing.

These men should know exactly what to look for and exactly what to do if you are having a problem with this important device. One thing you should know is that if you have a ceiling tstat you will not have a freeze sensor.

If you have a wall tstat then you will have a freeze sensor. Double-check to make sure this information is correct so you do not make a mistake and bypass a part that may be causing you the problem.

How To Recharge a Coleman Mach Air Conditioner


A Coleman air conditioner is supposed to be a closed system. That means that whatever Freon on you have inside is meant to last you forever. That is unless you get a leak somewhere. Then you have to recharge after you find and repair the leak.

You can do the recharging of this system yourself, but you will need special equipment to handle the task. You would need access valves and a recharge kit to handle the job. Plus, you may even need a special license to buy the Freon to put inside.

The easiest way to recharge a Coleman AC unit is to let an experienced and professional technician do it for you. It may be a bit more expensive this way but then you will not have that extra equipment lying around that may never be used again.

Also, you may not have the expertise to hunt down the leak and plug it up. You may need replacement parts to handle that repair. The technician will know and have those parts or can get them easier than you can.

This is a tough job to do so let those trained to do it handle the work and make sure it is done correctly.

How do I Reset my Coleman Mach Air Conditioner?

For the thermostat model 9630-3361, all you have to do is turn the thermostat off and then move to the fuse location. Pull the fuse and keep it out for 5 minutes. After that time frame, put the fuse back in and wait another 5 minutes.

When those 10 minutes are up, turn your thermostat back on. The Mach AC unit should be reset. This seems to be the standard reset method but just in case, check to see if your model has a reset button or not.

Or you can check your owner’s manual to make sure there is no reset button and get any different instructions to reset your Coleman AC unit. If still in doubt, call a dealer near you who can advise you on this issue.

The manual we checked did not give out that kind of information. It was focused on installing different parts and may only be a small portion of the actual manual. Double-check with a technician to make sure as upgrades happen all the time.

Models change or have slight differences thus one set of instructions may not be universal in application.

Downloading a Coleman Mach Manual


There are many sources for Coleman manuals. The hard part is sorting them out from all the other manuals Coleman publishes for its different products. The one we have used for this article can be found here. It has several diagrams to help you along with instructions to install different parts.

Another source for a manual will be found here. It has several different Coleman manuals and you can check if they will work for your specific model of an air conditioner.

Next will be this website. It is the manufacturer behind the Coleman Mach AC and other AC units. If you can’t find what you are looking for, just contact them and ask for some help.

Then there is this website. It goes right to one manual but there seem to be links to access different Coleman manuals. A good search on your part should turn up more options if these do not work for you for some reason.

Or if you want a hard copy, check with the many dealers or repair shops to see if they have any on sale. Or contact Coleman directly to see if they have an electronic version or a hard copy they can send you.

Some Final Words

Troubleshooting your Coleman Mach AC unit will sometimes be easy for you to fix. Sometimes, you have no other choice but to call a technician to handle the job. But as we keep reminding people, always check the easiest sources to fix first.

That way you save on embarrassment when all the problem is a loose wire or a blown fuse. The guide above should help you identify when it is time for you to handle the task and when it is time to call in a professional.

The drawback to calling a professional is that they may not have time to help for a few weeks.

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