Symptoms of a Bad or Failing AC Control Module

The AC systems found on modern vehicles are sophisticated systems that can come equipped with an array of sensors and components. The AC control module is used to control and regulate all the functions of the AC system electronically. It reads data from the cabin and the outside of the vehicle and uses that information to regulate and adjust the AC system as needed to keep the cabin at the correct temperature.

As the AC control module basically controls the entire electronic side of the AC system, any problems with it can have a dramatic effect on the entire system and should be inspected. Usually when a control module has begun to fail, it will begin to show symptoms that can alert the driver of a problem.

1. Inconsistent cooling

Because the AC control module controls and regulates all of the functions of the system, you may begin to notice cooling inconsistencies when there is a problem. If the cabin temperature is unable to reach, or struggles to maintain, the correct temperature, then that may be indicative of a problem with the AC control module. Since the module is what controls the system, any inconsistencies in the behavior of the system may be attributed to the module.

2. Out-of-date software updates

The AC control module is essentially the dedicated computer for the AC system, and similar to any non-automotive computer, it may require software updates to alleviate issues that may arise over time. Due to the nature of computer programs, any issues or bugs with the control module’s software may not present themselves until later in the vehicle's service life or until after the vehicle has been on the road for a few years.

With this in mind, some manufacturers will provide software updates for their systems if they find a problem or bug with the software. Owners can find out if any updates are required for their vehicles’ computer systems by checking the latest service bulletin for your vehicle.

3. Uneven air distribution

Aside from controlling and regulating the temperature functions of the AC system, the AC module is also sometimes responsible for directing the airflow to the correct vents. If you notice that certain vents are not blowing air, then this may be a sign that the control module could possibly be having a problem. When a module is beginning to fail, air may blow only out of certain vents or under certain settings.

Since the AC control module is basically the control computer for the AC system, any problems with it will negatively affect the entire system. If you suspect that you may possibly have a problem with your AC control module, have it diagnosed by a professional technician, such as one from YourMechanic. If necessary, they will be able to replace your AC control module to help alleviate any issues with your AC.


Next Step

Schedule Heating AC Inspection

The most popular service booked by readers of this article is Heating AC Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Heating AC Inspection reviews

Excellent Rating

(68)

Rating Summary
62
4
0
1
1
62
4
0
1
1

Ben

41 years of experience
1410 reviews
Ben
41 years of experience
Volkswagen Beetle L5-2.5L - Heating AC - Houston, Texas
i am well satisfied with Mr Smith working on my car(s). He replaced the Jaguar fuel pump like an expert, and then he diagnosed the VW bug ac compressor and fixed it on the spot. I would recommend him to anyone with a car issue
Nissan Altima - Heating AC - Houston, Texas
Incredibly nice and took the time to show me the problem, including comparison pictures between my unit and what a new unit should look like.

Peter

43 years of experience
1321 reviews
Peter
43 years of experience
Saab 9-3 L4-2.0L Turbo - Heating AC - Phoenix, Arizona
He knows what he's doing. Very polite and explained everything. I would no doubt use him again. I highly recommend him.
Mazda Miata - Heating AC - Peoria, Arizona
We are so thrilled to have found Peter as our new mechanic. He is very thorough and knowledgeable. He is also friendly, professional, and extremely honest. He explained to us exactly what services were needed on our vehicle to repair the air conditioner and provided us with an written estimate of the cost. He literally saved us thousands of dollars in repair costs. A local major competitor quoted us a repair cost of a minimum of $1,400 and said that the cost would go up to $2,400 if they discovered an additional part was required. Peter charged us only $202, plus performed the work at our home. The air conditioner in our 2004 Mazda Miata has honestly never worked so great--it always blew out warm air. We just assumed it was how that particular car was manufactured. We would highly recommend Peter to anyone who is in need of an experienced and honest mechanic.

Pedro

31 years of experience
78 reviews
Pedro
31 years of experience
Chrysler PT Cruiser L4-2.4L - Heating AC - Portage, Indiana
Pedro was wonderful! He was early first and foremost. He was very professional and he explained things to me. He worked quickly and was very thorough. Very happy with his service.

Manuel

32 years of experience
580 reviews
Manuel
32 years of experience
Ford Taurus V6-3.0L - Heating AC - Long Beach, California
Good guy. Knows his stuff. Knowledgeable and straightforward with diagnostics and repair costs. I’d love to work with him again! Thank you Manuel!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

How to Replace an AC Accumulator
The accumulator in the air conditioning system is faulty if there is rattling inside of it or there is a moldy smell emitting from the AC system.
How To Keep Your Car From Overheating
Monitoring your coolant level, turning the A/C off in very hot weather, and regular inspections will help you avoid having an overheating car.
How Does a Car Air Conditioning System Work?
Auto air conditioners serve well on hot summer days to make driving more pleasant by cooling the air and removing excess moisture in the car.

Related questions

Having problems with my air conditioner putting out different temperatures from different vents
Hello. Typically when you experience only one side of the system doing this, it is because of a bad air door actuator motor. These are common failures on most cars. If I knew what kind of vehicle this was, I...
Crank no start
Hey there, thanks for asking about your 2002 Ford Crown Victoria. Burned wires can signify that there has likely been a short somewhere in the electrical system. Often times when this happens, it is quite easy for the car's computer...
Why does the AC stop cooling the car once the car speed exceeds about 80 Km/h?
The A/C thermal expansion valve (TXV) ([https://www.yourmechanic.com/services/expansion-valve-orifice-tube-replacement]) most likely is the cause of the A/C system freezing up at higher engine or vehicle speeds. The TXV controls the flow of refrigerant through the evaporator and the valve can stick open...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com