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 Out-of-date software updates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.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing AC Control Module and was authored by Eduardo Ruelas.