The ECM/PCM signal controls the level of engagement of the EV clutch. An internal solenoid opens a spring loaded valve which allows silicone drive fluid to flow from the storage reservoir to the working area of the unit engaging the clutch. This engagement process is ultimately controlled through the ECM/PCM by the following input variables: Coolant Temperature, Intake Manifold Temperature, Transmission Oil Temperature, A/C Pressure and Engine Oil Temperature. These variables are manufacturer specific and fan speed is dictated based on the level of cooling required. Please consult the Original Equipment specifications to determine which set of variables apply to your vehicle.
Troubleshooting
During engine start up, the EV fan clutch will engage and match engine speed for up to 3 minutes. This is considered normal and may last more than 3 minutes in cooler climates or at lower driving speeds resulting in fan roar. This condition will cease shortly upon disengagement. Additionally, you may hear an audible "clicking" sound when the vehicle is stationary. These conditions are normal and should cease once the fan clutch disengages.
Installation & Diagnosis Notes
Do NOT replace EV fan clutch unless a specific issue is identified by proper SI (Service Indicator / Check Engine) diagnosis.
Do NOT replace an EV fan clutch for fan noise.
Do NOT replace an EV fan clutch unless a specific condition related to the EV fan clutch is identified using SI diagnostics. If the EV fan clutch has a condition that warrants replacement, a DTC (Diagnostic Trouble Code) should set and/or SI diagnostics should lead to the replacement of the fan clutch.
Do not attempt to replace EV Fan Clutch without proper tools. Please refer to manufacturer requirements for proper tools and replacement.
Q: Which Rotation Water Pump Do You Have: Standard or Reverse? A: Look at Your Pulley to Find out!
Reverse Rotation Pumps have a Smooth Pulley, which runs on the back side of the belt.
Standard Rotation Pumps have a Grooved Pulley, which runs on the inside of the drive belt.
During initial engine start up, the electronic fan clutch may produce a loud fan roar or an audible click for up to 3 minutes - this is normal. The noise will cease shortly after disengagement.
Additional Resources