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Mitsubishi Outlander AC Light Flashing – Why And What To Do?

The air conditioner in your Mitsubishi Outlander maintains the desired temperatures inside the vehicle. Could there be something wrong when the AC light starts flashing? To answer this question, we researched to bring you the following information.

The main component of the AC in your car is the compressor clutch. If it's faulty, it will cause the AC light to flash continuously. The reasons why the compressor clutch stops working could be due to:

  • Faulty compressor clutch
  • Faulty pressure switch 
  • Faulty compressor clutch relay
  • Worn compressor belt
  • Faulty compressor speed sensor
  • Faulty cooling fan
  • Low refrigerant

Read on to understand why the AC light in your car is flashing and how to solve this issue. Included also are the repair costs to stop the AC light from flashing.  

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A woman caught the steering wheel of a car while driving to work - Mitsubishi Outlander AC Light Flashing - Why And What To Do

Reasons The AC Light In Your Mitsubishi Outlander Flashes And What To Do

Car air conditioning system. Air condition switched on maximum cooling mode.

The AC keeps the inside of your car cool during the sweltering heat of summer. However, something is wrong with your air conditioner when the AC light flashes persistently.

When this happens, you need to check your AC, beginning with the compressor clutch.

Faulty Compressor Clutch

The AC compressor is the core of your vehicle's air conditioning system. When the compressor clutch turns, it communicates to the AC compressor to start moving.

In other words, when you press the AC button, the clutch alerts the compressor to compress the refrigerant, which activates the AC system in your car.  

You can find this compressor on Amazon.

When the compressor clutch is faulty, the AC light in your car will begin flashing. It means the clutch is not turning as it should, and subsequently, the AC will malfunction.

Soon after, you may experience higher temperatures in your car than you had previously set. As your car's heat rises, turning off your AC can become difficult.

This can happen due to a broken clutch. It prevents the compressor from being deactivated. Instead, it will continue running despite your efforts to turn it off.  

You may start to hear strange noises in your vehicle. When the bearings in the compressor are worn out, they produce a piercing, squealing sound. If the bearing has been seized, it will make a grinding sound. 

Faulty Pressure Switch

The pressure switch is responsible for turning the compressor on and off. It prevents the AC from turning on when the refrigerant is low.  

The switch may also work intermittently and then stop for a short time. You will likely feel warm air blowing out of the AC after turning it on. You might also hear strange noises coming from your AC.

Check out this universal AC pressure switch on Amazon.

There are several ways of finding out why your pressure switch is bad. One of the methods is by scanning with an OBD2 scanner. Fix it to the OBD2 ports in your Mitsubishi Outlander and scan for the faulty pressure switch codes.

Another method is by checking for continuity in the pressure switch. Here's a video on how to go about this.

If your pressure switch is faulty, you can replace it by following the steps in the video below.

Faulty Compressor Clutch Relay

The AC compressor relay supplies electrical power to the AC compressor and clutch for the AC system to function. Over time, the relay can wear out or burn out and begin to fail. The result is the AC inconsistently cooling your car. 

Find out from your owner's manual where the relay is located, then use a multimeter to check if the relay is faulty. 

For a Mitsubishi Outlander, you will find it in the instrument panel on the driver's side. Check on the left side of the steering wheel, and you will see it behind the cover. 

After locating the relay and pulling it out from the fuse box, connect the pointers to the terminals of the relay. It is still working if the reading is between 40 and 120 Ohms. 

Have a look at this automotive AC compressor relay on Amazon.

If the reading is out of range, you need to replace it, as shown in the video below.

Worn Compressor Belt

Your Mitsubishi Outlander either has a serpentine or V-shaped AC compressor belt. The AC compressor clutch is connected to the engine crankshaft by the belt. When power runs from the engine, it allows the belt to turn the compressor.  

You can find this serpentine compressor belt on Amazon.

A worn belt will eventually malfunction. You will know it is not working when a squealing noise comes from your AC when you turn it on. 

When you examine it physically, you might find cracks in it and, worst-case scenario, a broken belt. A faulty belt needs to be replaced with a new one.

Check out how to do this in the video.

Faulty Compressor Speed Sensor

The AC compressor speed sensor is responsible for preventing the compressor from locking down by comparing the speed of the engine and the compressor. If it's faulty, your AC will not function properly.

You can use the OBD2 scanner to check if there are any error codes. If there are, the speed sensor is not working and will need replacement. You can also use a multi-meter; replace it if there is no voltage.

Watch the video below on how to check for voltage in a speed sensor using a multi-meter.

Faulty Cooling Fan

A blown fuse or a cracked cooling fan will keep your AC from functioning well. When the fan is faulty, your condenser will not cool properly.

Faulty wiring or a defective fan control module are other reasons the fan could have stopped working. The solution is to replace it.

A woman caught the steering wheel of a car while driving to work.

Low Refrigerant

One of the most common reasons your clutch could be faulty is when the refrigerant in your car's AC system is too low. Ideally, your vehicle should not lose any refrigerant since it runs in a closed system. It usually lasts up to 5 years. 

Find this manifold gauge set on Amazon.

But your car is probably leaking if you have to keep filling up the refrigerant. Use a manifold gauge to check the pressure of the AC system. Depending on the refrigerant levels, the AC pressure switch turns on or off the air conditioner.

The AC pressure switch detects when the refrigerant level is low and will not turn on the AC. Most cars will read 25 to 30 PSI when the pressure is low at an ambient temperature between 70 and 80 degrees Fahrenheit. 

How To Check The AC Pressure

Car air conditioner check service, leak detection, fill refrigerant.Device and meter liquid cooling in the car by specialist technicians

To check how low the AC pressure in your Mitsubishi Outlander is, first find out the type of refrigerant in the AC system. You can check this from your manual. 

Below is a table showing the recommended low range of refrigerant temperature readings in a Mitsubishi Outlander. This is after testing the AC pressure in different ambient temperatures: 

Ambient Temperatures

Fahrenheit

Refrigerant-1234yf

Refrigerant-134a

110

40 to 55 psi 45 to 55 psi

100

35 to 45 psi 45 to 55 psi

90

30 to 40 psi

45 to 55 psi

80

25 to 35 psi

40 to 50 psi

70 20 to 30 psi

35 to 40 psi

The refrigerant may be low if you find a lower deviation than any of the readings above. There could be a leak in your vehicle due to holes or cracks in the refrigerant lines.

If the leaks are severe, the refrigerant levels can be dangerously low. As a result, the compressor may finally seize up because it has to work twice as hard to pump the little fluid left moving throughout the system.

Seal the holes and cracks to solve this problem. There are several ways of solving this problem, though your mechanic can advise you on the best possible solution.

Check out this aluminum AC line splice connector on Amazon.

However, an AC line splice like the one above can seal the holes or cracks. The video below demonstrates how to seal the holes or cracks using a splice.

Cost Of Fixing AC Issues In Your Vehicle

Labor costs to replace the AC compressor in a Mitsubishi Outlander Sport are between $158 and $200. The parts cost roughly between $1,358 and $1,907.

But,you may only need to replace the compressor clutch, not the whole compressor. On average, the cost estimate for the part is between $450 and $850 and from $150 to $250 for labor. 

You will pay between $61 and $77 to hire a professional to replace the AC pressure switch in your car. The sensor will cost you around $278.

Generally, whatever repair or replacement you need to do to remove the AC flashing light will depend on several factors. Some include your location and the year and model of your car. 

image of Car air conditioning

In Closing

The AC light flashing on the dashboard of your Mitsubishi Outlander means there's a problem with your AC. The compressor is the main component of your car's AC system. A failing AC is primarily due to a faulty compressor clutch.

In this post, we covered several ways of diagnosing which part has malfunctioned and provided solutions. 

For more information on car air conditioners, you may read our previous posts below:

Air Conditioner Only Works When Driving

How Long Can A Car Battery Run An Air Conditioner