Impreza Wagon AWD F4-1820cc 1.8L SOHC (1993)
A/C Signal: Description and Operation
A/C Circuit
PURPOSE
When 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 recives 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.
LOCATION
The A/C switch is located in the HVAC control panel. The throttle position sensor is attached to the throttle body.