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Ford Mustang GT 2005-2014: Why Won't My A/C Work?

Fixing your air conditioner may not be as expensive as you think. Use this article to help diagnose what the problem is.

By Neftali Medina - October 7, 2015
Contributors: Mustang Forums, IMR, Sparky Answers, Al lFord Mustangs, Home Air Today

This article applies to the Ford Mustang GT (2005-2014).

No one likes to experience a broken air conditioner, as it is commonly associated with requiring a large sum of money to repair. However, many car owners fail to realize there are some basic issues that can stop an air conditioning system from working. This article highlights some common issues that can cause the air conditioning system to fail in your Ford Mustang.

Materials Needed

  • Multimeter
  • Test-light
  • Air conditioning gauge

Step 1 – Check your fuses

An A/C fuse may have blown.

Boy I gotta tell ya, there is no better feeling than finding out a major problem can be fixed with less than $5. Like all the electrical components on your car, the air conditioning system has several fuses that protects it from any power surges or electrical faults. Open the fuse box up, remove the fuse and inspect it. Even if the prongs look healthy, use a test-light to check the fuse for conductivity. If the fuse is damaged or not receiving any electricity, replace it and check the A/C.

Figure 1. Check your fuses.

Pro Tip

If the fuse is not receiving any power, then there can be an issue with the actual wiring. So, take the time to thoroughly inspect both the wiring and fuse prior to checking the other components.

Step 2 – Check the blower motor

The motor may have failed.

The next thing to check for is the blower motor or resistor for the blower motor. Both components are located in the same place, so look behind the glove box to see the assembly. Test the resistor pack with a multimeter and see if it is receiving the proper amount of voltage. You can also go purchase the resistor for less than $20 and swap it out if you are lazy, but it may not be necessary if the piece works. If the resistor is in working order, check the actual blower motor. If either unit is failing, replace the component.

Figure 2. Blower motor resistor.

Step 3 – Check your pressure

There may be a leak.

The air conditioner uses a pressurized system to cool the air. When the refrigerant in the hoses leak out, the compressor will not be able to pressurize it and cause the air to stay warm. With the engine running, turn the air conditioning system on and attach a gauge to the low pressure port. If it reads approximately 35 PSI, then you have a leak-free system. However, if it reads less, then you'll have to find out where the Freon is leaking from to make the repair.

Figure 3. Check the A/C pressure.

Step 4 – Check the compressor

It may have failed.

The compressor is the core of an air conditioning system. As mentioned above, it pressurizes the Freon and makes it cold. When a compressor fails to engage, it can become seized or may simply not turn on. Unfortunately, there is no cheap way to replace one of these, as you will have to legally remove the refrigerant, remove and install the unit, then refill the Freon.

Figure 4. A/C compressor.

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