Laser FWD L4-1753cc 1.8L SOHC (1993)
A/C Signal: Description and Operation
A/C Circuit
Operation
When the driver turns on the A/C system, a positive voltage signal is supplied to the ECM (as an indication that the A/C system is needed) and to
one side of the A/C relay coil, located on the left fender apron near the firewall.
The ECM determines if engine conditions are suitable for A/C operation (idle speed, ignition timing and air/fuel mixture). If the ECM senses that
conditions are suitable for A/C operation, it supplies the ground circuit for the A/C relay coil, energizing it. This allows the relay to supply voltage
to the compressor clutch.
