Colt Vista 2WD L4-1795cc 1.8L SOHC (1992)
A/C Signal: Description and Operation
A/C Circuit
OPERATION
When the driver turns on the A/C system, a voltage signal is supplied to the ECU (as an indication that the A/C system is needed) and to one side
of the A/C relay coil, located on the right fender apron relay box near the firewall.
The ECU determines if engine conditions are suitable for A/C operation (idle speed, ignition timing and air/fuel mixture). If the ECU 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.
