Scoupe L4-1468cc 1.5L SOHC VIN J MFI (1994)
System Relay: Description and Operation
A/C Switch And Relay Circuit
PURPOSE
The Air Conditioning Relay supplies current to the A/C compressor clutch when the ECM determines that engine conditions are suitable for A/C
operation.
LOCATION
Located behind the drivers side dash, in the relay box.
RELAY OPERATION
The relay is electromechanical. The ECM monitors the A/C on signal from the switch to the relay. When voltage is supplied from the switch to the
relay coil, the ECM supplies the ground circuit to the relay coil (if conditions are suitable). This energizes the relay, closing the contacts.
SYSTEM OPERATION
When the air conditioner switch is turned on, with engine at idle, the ECM activates the ignition power transistor and Idle Speed Control (ISC)
actuator to increases idle speed. To eliminate air conditioner load during that delay period, the ECM keeps the compressor power off for about 0.5
seconds. As a result, even if the air conditioner switch is on, the air compressor is not driven instantly.
