Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Cooling Fan - Transit
The primary cooling fan is a mechanical fan driven by the engine. The fan speed is relative to the engine RPM depending on the ambient air temperature.
The secondary cooling fan is electric and controlled by the PCM. 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 secondary fan operation through the low fan control (LFC), high fan control (HFC) outputs.
The PCM output circuits are called low and high fan control, and the secondary cooling fan speed is controlled by a combination of these outputs.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.