3000GT V6-2972cc 3.0L DOHC (1993)
Air Conditioning Switch: Description and Operation
Air Conditioning Switch And Relay 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 LH inner fender panel. The ECM determines if engine conditions are suitable for A/C operation
(engine temperature, idle speed, ignition timing and air/fuel mixture).
If the the engine coolant temperature switch is closed (temp. below 235° F) the A/C ON signal is transmitted to the ECM. 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.