Possible Causes
Faulty Cooling Fan Relay
Cooling Fan Relay harness is open or shorted
Cooling Fan Relay circuit poor electrical connection
Faulty cooling fan clutch
Faulty control unit
الأسباب المحتملة
Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
الأعراض المحتملة
Description
The cooling fan relay sends a Pulse Width Modulation (PWM) signal of 12 – 14 volts to the cooling fan clutch through the cooling fan clutch solenoid voltage control circuit. The cooling fan relay varies the voltage drop across the cooling fan clutch solenoid in relation to a pulse width modulated signal from the Engine Control Module (ECM) in order to control the speed of the cooling fan. The signal controls the position of the oil control valve inside the cooling fan clutch housing. The Diagnostic Trouble Code (DTC) will be set if the clutch fluid pump-out, which is the time it takes for the fan clutch to disengage completely, is greater than a range of 10 minutes at sea level to 52 minutes at elevations of 6, 500 ft.
