A/C

When the A/C compressor is activated, either by the ACC control module or by means of the A/C button on the dashboard, battery positive voltage is applied to pin 40 of the Motronic control module.

The control module then opens the idle air control valve slightly more to prepare for the forthcoming load increase. After a short delay the control module grounds pin 25, which is connected to the A/C relay.

The control module breaks the circuit to pin 25 before the motor has actually started.