Engine Cooling Fan: Operation
Fan will always operate when A/C compressor clutch is engaged. The fan will also operate when coolant temperature sensor verifies coolant temperature has reached 185°F (85°C). The coolant temperature sensor contacts close, causing current to flow through the radiator fan relay to the fan. The fan will shut off when coolant temperature is 172°F (78°C) or less.
On A/C-equipped models, when A/C is on "HIGH" setting and coolant temperature exceeds 185°F (85°C), the condenser fan motor relay is on. This operates the condenser fan and radiator fan assembly at high speed. When A/C is on "LOW" and coolant temperature exceeds 185°F (85°C), radiator fan assembly is on. See SYSTEM OPERATING CONDITIONS table.
On A/C models, the A/C control unit activates the fan assemblies. The A/C control unit will produce a 12-volt (high) signal if the ignition switch, blower switch, A/C switch or compressor clutch is engaged. If any of the switches or 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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