Electric Cooling Fan
| ITEM | DESCRIPTION |
|---|---|
| 1 | Cooling fan shroud |
| 2 | Cooling fan blade |
| 3 | Electrical connector |
| 4 | Electric cooling fan motor |
| 5 | Speed flap (8 off) |
The variable speed electric cooling fan is installed in a shroud attached to the rear of the radiator. The electric cooling fan is operated by the engine cooling fan control module, integrated into the electric motor. The engine cooling fan control module is controlled by the Powertrain Control Module (PCM) through a Pulse Width Modulation (PWM) signal. An electrical connector at the right side of the shroud provides the interface between the electric cooling fan harness and the vehicle wiring.
The engine cooling fan control module is provided with:
- A battery power supply from the Engine Junction Box (EJB)
- An ignition signal from the PCM relay in the EJB
- A PWM signal from the PCM
- A ground.
The system is protected against abnormal internal temperature by measuring its internal temperature at two points with temperature sensors.
- Sensor 1: This sensor is used to calculate the temperature of active components near the micro controller. The fan will stop immediately if the fan internal temperature reaches 135°C (275°F). At motor stop, after a delay of 120 seconds the diagnostic feedback will be sent. Normal operation will resume when the temperature is less than 120°C (248°F).
- Sensor 2: This sensor is used to measure the temperature of the power stage of the Printed Circuit Board (PCB). It reduces the power if the temperature is too high and to stop the motor in case of an over temperature condition.
The electric cooling fan will derate if the powerstage internal temperature reaches 135°C (275°F) and stop motor function at 145°C (293°F). At motor stop, after a delay of 120 seconds the diagnostic feedback will be sent. Normal fan operation will resume when the powerstage temperature falls to 135°C (275°F).