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Ford Mustang V6 2005-2014: Why is My A/C Blowing Warm Air?

Does your A/C blow hot air right after you turn it on? This diagnostic is here to help you figure out why it's doing that.

By Jared Hammond - October 19, 2015

This article applies to the Ford Mustang V6 (2005-2014).

You hop into your Mustang, turn on your A/C, and what do you get? A blast of hot air. When your A/C only blows warm air, it can make driving uncomfortable. There are a number of things that can cause your A/C to behave this way. Keep reading to learn more.

Materials Needed

  • A/C recharge kit
  • Screwdrivers and socket set

Step 1 – Does the system need recharging?

If the A/C fails to blow cool air at all, it could mean that the system is low on R134a refrigerant. Sometimes, you can tell if you're low by watching the compressor while the A/C is running. If the clutch on the compressor rapidly stops and starts, then you're low on R134a.

Figure 1. R134a canister with pressure gauge.

One thing to check before you buy a recharging kit is to look for leaks, as this is what usually causes a drop in R134a levels. Recharging a leaky A/C system is just a waste of time and money. There are kits available that include a dye in the R134a that will allow you to detect leaks in the system. If you have a leaky system, it'll require evacuating the system and replacing the leaky components. This is best left to a dealership since it requires precision and special equipment.

Pro Tip

Always recharge your A/C system through the low pressure valve.

Step 2 – Are the blend doors stuck?

When the A/C is stuck on either hot or cold air, it could be because the blend door that switches between vents is stuck in one position. This can happen when the actuator motor that turns the door stops working. If you hear clicking noises when you turn the A/C on, it's probably because of a broken actuator.

Figure 2. Blend door actuator with a broken gear.

There are multiple actuators in the Ford Mustang, but the one you should check is located behind the left panel of the glove compartment. The actuator is easy and inexpensive to replace. It's just held up by a couple of screws. Just make sure that the shaft of the actuator is lined up with the blend door vent.

Step 3 – Replace the orifice tube

A bad orifice tube can result in an overload of refrigerant in the evaporator, which causes the system to freeze. The orifice tube is located between the compressor and the evaporator, near the firewall of the Mustang. This is also a cheap and simple part to replace.

Step 4 – Check the pressure switch and compressor

The pressure switch on your compressor is what turns the compressor on and off by sensing the pressure in the lines. A failed pressure switch can result in your system freezing and failing to blow cool air. If you've noticed your compressor is only running a cycle every few minutes, you could have a bad pressure switch.

Another possibility is there is something wrong with the compressor itself. This is not usually the case unless there is air in the system, the wrong oil is used in the compressor, or if the compressor is leaking internally. The only thing that can be done for a failing compressor is to replace it.

Figure 3. A/C compressor.

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