The AC control switch is a very important component of the AC system. It is the physical switch that allows the user to turn on and change the settings of the AC system from inside of the vehicle. It is usually a custom panel with knobs and buttons that allow the user to control the functions of the AC system, such as setting, temperature, and intensity of the fans. Aside from allowing the user manual control over the AC system, the switch can also sometimes serve to control and regulate certain functions automatically.
The AC control switch is basically the user’s control surface for the AC system. When there is a problem with the switch, it can cause all sorts of problems and quickly take away from the functionality of the AC system, so it should be inspected as soon as possible. Same as with most components, there will usually be a few warning signs that will help inform the driver if the AC control switch has failed, or is beginning to fail.
1. Overheating AC parts
One of the first signs that the AC control switch may be having a problem is that certain parts of the AC may overheat. The AC control switch is essentially an electronic circuit board with knobs and switches. In certain cases, the switch may short circuit or develop a resistance problem, which may cause the switch itself to overheat. It may become hot to the touch and begin to malfunction or not function at all.
The switch also distributes power to other AC components. Therefore, a problem with the switch may cause other components to overheat, due to excessive power or heat. Usually when a switch is hot to the touch, it has malfunctioned and needs to be replaced.
2. Certain settings not working or working intermittently
As the AC control switch is an electrical switch, it contains electrical contracts and knobs that can wear and break. A broken knob or completely worn out electrical contact inside of the switch may cause one or more of the settings not to work, or to work intermittently. Usually, the switch must be replaced if this occurs.
3. AC compressor not coming on
Another symptom that may present itself when the AC control switch has failed, is the compressor not coming on. The AC control switch is what powers and controls the AC compressor, as well as the entire system. If it is not working properly, then the AC compressor may not come on, which will prevent the AC from blowing cold air.
In most cases a bad or failing AC control switch will display noticeable symptoms that hint that there is a problem with the switch. If you suspect that your switch has failed, have it diagnosed by a professional technician, such as one from YourMechanic. They will be able to inspect your system and replace your AC control switch if necessary.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing AC Control Switch and was authored by Eduardo Ruelas.