Integra Type R Coupe L4-1797cc 1.8L DOHC (VTEC) MFI (2001)
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Evaporator Temperature Sensor / Switch: Description and Operation
When the ignition switch is in ON (II), voltage is applied to the coils of the radiator fan relay and the condenser fan relay (with A/C) through fuse 17.
Whenever a ground is provided to the radiator fan relay and condenser fan relay, the relays are energized, turning ON the radiator fan motor and
condenser fan motor. The relays can be grounded by the engine coolant temperature switch, Engine Control Module (ECM) (USA), or the A/C and
heater fan switches via the A/C pressure switch and the A/C thermostat.
The A/C thermostat is located on the evaporator housing. The A/C thermostat turns OFF the A/C compressor clutch if the temperature at the evaporator
goes below 3°C (37°F). This prevents condensation from freezing on the evaporator fins and blocking the air delivery into the passenger compartment.
The blower motor will keep running when the sensor turn OFF the compressor.
If the temperature goes below 3°C (37°F) turning OFF the A/C thermostat, and the BLU/RED wire at the A/C diode was the only wire providing ground
to the condenser and radiator fan relays (A/C switch ON, heater fans switch ON, engine coolant temperature switch open, and ECM fan control output
not grounded), the relay will deenergize removing voltage from the condenser and radiator fan motors causing them to stop running.
