F 550 4WD Super Duty V8-6.0L DSL Turbo VIN P (2003)
Radiator Cooling Fan Speed Sensor: Description and Operation
Fan Speed Sensor (FSS)
The fan speed sensor is a Hall-Effect sensor integral to the vistronic drive fan (VDF). The powertrain control module (PCM) will monitor the sensor
input and control the VDF speed based upon engine coolant temperature (ECT), transmission fluid temperature (TFT) and intake air temperature
(IAT) requirements. When an increase in fan speed for vehicle cooling is requested, the PCM will monitor the FSS signal and output the required
pulse width modulated (PWM) signal to a fluid port valve within the VDF.
