A/C Signal: Description and Operation
PURPOSEWhen received by the ECM, the A/C switch signal causes the ECM to make adjustments needed (such as raise idle speed) to compensate for the added load. When the ECM receives a "full open" signal from the throttle position sensor while the A/C is operating, the A/C cut relay turns off the compressor for a certain period. This improves full-throttle acceleration.