IHKA E36 Compressor Control

Fig 1: IHKA E36 Compressor Control Circuit Diagram

When A/C is requested (by pressing the "snowflake"), the IHKA control panel/module sends a request signal to the engine control module.

If A/C refrigerant pressures are within limits, the engine control module stabilizes engine idle and determine whether or not to energize the A/C compressor clutch (by grounding the compressor control relay).