Forester S F4-2.5L DOHC (1998)
System Relay: Description and Operation
THERMO CONTROL AMPLIFIER
The thermo control amplifier disconnects the magnet clutch circuit to prevent the evaporator from becoming frosted when the temperature of the
evaporator fin drops close to "3 °C (37 °F)". As the evaporator is cooled, the thermistor (located on the evaporator fin) interrupts the "base" current of
the amplifier. This in turn deenergizes the A/C relay coil, which in turn disconnects the magnet clutch circuit.
