Max Cooling Fan Strategy
The radiator cooling fan used on the engines replaces the engine driven mechanical fan and the hydraulically controlled fan. This provides max cooling at 850 watts to the vehicles that require the additional cooling.
The radiator cooling fan is controlled by the PCM. A PWM (Pulse With Modulated) signal from the PCM controls the fan speed.
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 send a signal to the fan module to slowly ramp up (speed up) the fan speed until the parameter(s) are under control. Once the temperature is reduced to within operating parameters the fan will ramp up, ramp down, or hold its speed to maintain the temperature requirements, while reducing unnecessary power drain on both the engine and the vehicles electrical system and keeping the NVH of the fan low.