A/C Signal: Description and Operation

The A/C compressor is switched off (during acceleration by the Engine Control Module (ECM) and at wide open throttle by the Transmission Control Module (TCM) via the kickdown switch.

A/C compressor shut-off is bi-directional ("in "and "out").

- IN: Shortly before switching the A/C compressor on, voltage is applied to the ECM which causes the Idle Air Control (IAC) valve to open a little more to adjust to the higher load.

- OUT: When accelerating from a stand still position and at lower speed, the A/C compressor is shut off for approx. 12 seconds via control by the ECM. If the accelerator pedal is released early enough, the duration is reduced to a minimal 3 seconds.