Engine Cooling Fan: Operation
When coolant temperature reaches 185°F (85°C), coolant temperature sensor contacts will close, causing current to flow through the radiator fan relay to the cooling fan. Cooling fan will shut off when coolant temperature is less than 172°F (78°C).
A/C condenser fan will operate whenever A/C compressor clutch is engaged. When A/C is on and coolant temperature exceeds 185°F (85°C), the condenser fan motor relay is activated, operating the condenser fan and radiator fan assembly at high speed. When A/C is on and coolant temperature is less than 185°F (85°C), condenser fan and radiator fan assembly will operate at low speed. See SYSTEM OPERATING CONDITIONS table.
The fan assemblies are activated by the A/C control unit. The A/C control unit will produce a 12-volt (high) signal if the ignition switch, blower switch, and A/C switch or compressor clutch is engaged. If any of the switches or the coolant temperature sensor is off, no-voltage (low) signal will be delivered from the A/C control unit.
| Switch Position | Coolant Temp. Sensor | Radiator Fan | Condenser Fan | ||||
|---|---|---|---|---|---|---|---|
| A/C On Low (1) | Off | Off | Off | ||||
| A/C On Low (1) | On | High Speed | Off | ||||
| A/C On High (2) | Off | Low Speed | Low Speed | ||||
| A/C On High (2) | On | High Speed | High Speed | ||||
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