Why does my car ac compressor turn on and off?

Answer by  crock (25)

It sounds like the air conditioner is low on freon. You can recharge yourself if the system is a R134a. Most auto parts stores sell the kits with detailed instructions.

Answer by  Srfingfreak (697)

The AC compressor is driven by the control circuit which monitors the temperature inside the car. If the AC compressor is rapidly cycling, the control circuit is updating the temperature too quickly, or has its sensitivity turned too high.

Answer by  JordanW (12)

AC units with thermostats built in turn off at the proper temperature, conserving energy. If your car is cold when the compressor turns off, then this is likely the cause.

Answer by  Amber40 (24961)

Well like in a house unit the compressor is used to circulate coolant. It only does it when the temperature of the air rises to keep it cool.