Standard Cooling Fan Strategy
The radiator cooling fan used on the engines replaces the engine driven mechanical fan and the hydraulically controlled fan. This provides cooling at 350 watts to the light duty cooling systems on the vehicles. Helps in reducing unnecessary power drain on both the engine and the vehicles electrical system while keeping the NVH of the fan low.
The cooling fan is controlled by the PCM. A ground signal from the PCM is provide for the LOW fan relay. If the conditions are required for additional cooling. The PCM provides a ground to the HIGH relay.
There are three inputs to the PCM that determine what speed percentage of fan is required by the vehicle. These inputs are:
- Engine Coolant Temperature
- Transmission Oil Temperature
- A/C System Pressure
By monitoring these three parameters, the PCM can determine if cooling airflow is required. If airflow is required, the PCM will ground the required fan relay until the parameter(s) are under control. Once the temperature is reduced to within operating parameters the fan will ramp up or ramp down to maintain the temperature requirements.