F 150 4WD V8-5.4L Flex Fuel (2008)
Radiator Cooling Fan Motor: Description and Operation
FAN CONTROL
The PCM monitors certain parameters (such as engine coolant temperature, vehicle speed, A/C on/off status, A/C pressure) to determine engine cooling
fan needs.
For variable speed electric fan(s):
Edge/MKX, Taurus/Taurus X/Sable, Fusion/Milan/MKZ, Crown Victoria/Grand Marquis, Town Car: FCV Duty Cycle Output From PCM (Negative Duty Cycle)
The PCM controls the fan speed and operation using a duty cycle output on the fan control variable (FCV) circuit. The fan controller (located at or
integral to the engine cooling fan assembly) receives the FCV command and operates the cooling fan at the speed requested (by varying the power
applied to the fan motor).
For relay controlled fans:
2.0L Focus (With A/C): PCM FC Output State For Cooling Fan Speeds
2.3L Escape: PCM FC Output State For Cooling Fan Speeds
The PCM controls the fan operation through the fan control (FC) (single speed fan applications), low fan control (LFC), medium fan control (MFC), and
high fan control (HFC) outputs. Some applications will have the xFC circuit wired-to 2 separate-relays.
For 3-speed fans, although the PCM output circuits are called low, medium, and high fan control (FC), cooling fan speed is controlled by a combination
of these outputs. Refer to the table.
