A/C Control Unit
A/C control unit is located above A/C-heater unit. See Fig 1 . A/C control unit prevents idle speed from dropping due to A/C compressor load, ensuring a stable idle speed. A/C control unit sends A/C system on-off signal to ECM. When A/C is turned on and ECM receives signal from A/C control unit, ECM commands idle speed control servo to increase idle speed to a preset RPM.