A/C Compressor Signal

The A/C Compressor Signal is connected to pin 37 of the Motronic control module, the signal is bidirectional (PIN 37 - INPUT + OUTPUT).

This signal is a communication link between the A/C control, Motronic control module and the transmission control module. Signal flow to or from the Motronic control module is as follows:

Signal IN

^ Before switching the A/C compressor ON, the idle air control valve duty cycle is modified in order to compensate for the higher engine load.

Signal OUT - manual transmission only

^ The compressor is switched OFF for a maximum of 12 seconds at a vehicle speed of less than 4 mph when the throttle valve is opened quickly (acceleration).

Signal OUT - automatic transmission only

^ The compressor is switched OFF for a maximum of 3 seconds in first gear (recognized from vehicle speed and engine speed) with a throttle valve opening of more than 65° (full load).