How to Fix Your Car’s A/C
Entering a hot car and sticking to the seats because the air conditioning isn’t working is something no motorist wants to experience on a scorching day.
Sure, you could drive with the windows open and the fan blowing, but that’s not a comfortable solution – and it certainly won’t be popular with your passengers. That’s why we’re here to help you figure out the best way to fix your car ac, depending on the cause.
Signs You May Need Your Car’s A/C Repaired
Obviously, the main sign of broken air conditioning is that there is no air conditioning. The vents may be blasting hot air in your face or not blasting at all. Either way, once you’ve checked that the vents are open and the knobs are set to cool, then you’re probably pretty safe to assume the A/C is broken.
Air conditioning woes can range from major to minor. Here are the most common causes of broken car A/C systems:
1. Low refrigerant
This is the most likely issue when the air blows hot. A leak typically causes low refrigerant; a worn hose or a loose connection is often the culprit.
You can replenish the system using a recharge kit available at an auto parts store. Still, there are two downsides to that approach: One; there’s a risk of overcharging the system, which can adversely affect its performance. Two, you still won’t have found and fixed the leak that caused the problem in the first place.
2. Faulty compressor
If this key component fails, the entire air conditioning system is down. The compressor could have a bad clutch, which is a less-serious repair. In cars with a belt-driven A/C unit, the clutch connects the compressor to the pulley that powers the system; it allows you to turn the compressor on and off. (If your A/C unit is driven by an electric motor, as in some hybrids and all EVs, it won’t have a clutch.) The problem could be as simple as a blown fuse.
3. Bad pressure switch
A pair of pressure switches monitor the refrigerant. If the pressure becomes too high or low, it will turn off the compressor for safety reasons, which will cause the system to stop working.
4. Damaged condenser
The component that cools the air conditioning refrigerant sits ahead of the radiator at the front of the vehicle,e and it can become clogged or damaged from debris striking it. Age and wear can also cause a condenser to fail. A car’s A/C condenser will typically need to be replaced after 10 years or so under regular operation.
5. Failed condenser fan
The condenser uses moving air to cool the system’s refrigerant. When driving the vehicle at higher speeds, this takes care of itself, but the condenser needs a fan to function at lower speeds.
If the fan stops working, you’ll notice a difference in how well the A/C system cools the cabin while driving around town versus on the highway. You may also hear some banging or rattling, and you won’t hear the fan running after the car is parked.
6. Sensor glitches
A vehicle’s climate control system relies on numerous sensors to deliver air at the proper temperature. Its performance will be compromised if one of these sensors fails.
7. Obstructed cabin air filter
A car’s climate control system uses a filter to trap dust, pollen, and particles that might otherwise enter the cabin. If the cabin air filter is not changed regularly, it can become clogged and affect the system’s cooling abilities.
8. Defective blend door actuator
A vehicle’s air conditioning system uses a blend door actuator that channels hot or cold air into the cabin. If you set the system for one and get the other, it could be because the actuator is malfunctioning.
9. Faulty head unit
If the rest of the system checks out, the central control unit (the part in the cabin with the temperature controls) may be at fault, perhaps sending the wrong signal. This could result from a problem with the wiring or, in the case of newer vehicles, the electronic signal that links the computerized temperature controls to the mechanical A/C components under the hood.
How Much Does a Car A/C Repair Cost?
Some of the most severe problems can be costly, but this can be money well spent when the temperatures are sizzling.
Here’s a look at some national average estimates to repair the most common air conditioning woes, courtesy of RepairPal.com. Prices will vary according to the cost of parts for your specific vehicle, local wage rates, and other factors. Estimates do not include taxes and related service requirements.
- System Inspection: Up to $70
- Refrigerant Recharge: $120 to $155
- Blend Door Actuator Replacement: $325 to $375
- Cabin Air Filter Replacement: Up to $85
- Compressor Replacement: $720 to $950
- Compressor Clutch Replacement: $570 to $620
- Condenser Replacement: $450 to $600
- Condenser Fan Replacement: $385 to $475
- Electronic Control Module Replacement: $380 to $400
- Temperature Sensor Replacement: $320 to $400
DIY: Can You Fix Your Car’s A/C Yourself?
Air conditioner repair is best left to the pros, but you can do some air conditioner maintenance at home. An air conditioning system will last longer if it’s properly maintained.
Tips for maintaining your car’s A/C
- Run the system for at least 10 minutes each week at its highest fan and lowest temperature setting, even in the year’s coldest months. This basic process helps lubricate the compressor and prevent leaks. While you’re at it, run the defroster for 5-10 minutes to clear the system of any moisture or mildew.
- Change the cabin air filter according to your vehicle’s maintenance schedule.
- Have the refrigerant recharged every two years. This isn’t as easy as the first two steps, but kits are available online with detailed instructions.
- Finally, don’t hesitate to take the car in for service if the climate control system isn’t working as expected.
How a Car’s A/C Works
Though A/C systems have become more sophisticated over the years, with some offering up to four zones of individual temperature control, the basic air conditioning technology remains more or less the same.
- The system uses a compressor driven by a pulley connected to the engine or, in electric cars, an electric motor attached directly to the compressor.
- The compressor compresses low-pressure refrigerant gas to a high pressure.
- The pressurized refrigerant gas flows into the condenser behind the car’s front grille, where a twisting tube system cools the refrigerant into a high-pressure liquid.
- The high-pressure liquid refrigerant moves through an accumulator or receiver dryer, which removes any water that might damage the system.
- The high-pressure fluid passes through an orifice tube or expansion valve. This allows the refrigerant to expand and cool to move to the evaporator core as a near-freezing low-pressure liquid. In the evaporator, the liquid converts back to a low-pressure gas.
- A fan blows air over the evaporator and sends the cool air into the passenger compartment.
- The low-pressure refrigerant gas flows back into the compressor,r where the process begins over again.
Next Steps
- The Carfax Car Care app knows your car’s maintenance schedule and sends you automatic reminders when it’s time to service it.
- Carfax’s Service Shop Directory can show you the top-rated mechanics in your area.
If you have questions about this story, please contact us at Editors@carfax.com
