Variable Speed Electric Fans

WARNING: This page is about a different car, the 2024 Ford Transit-350 HD, 2024 Ford Transit-350, 2024 Ford Transit-250, and 2024 Ford Transit-150. However, it is still accessible from the selected car via links, so may be relevant.

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.

The PCM controls the fan speed and operation using a duty cycle output on the 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).

The fan controller is able to detect certain failure modes within the fan motors. Under certain failure modes, such as a motor that is drawing excessive current, the fan controller shuts the fans off. Fan motor concerns may not set a specific DTC. With the fan motor disconnected from the fan controller, voltage may not be present at the fan controller.