Cooling fan 1 speed control short circuit to 24V.
â–¶ How to fix
Check harness, check connectors. Measure output from BMU. If FAN is commanded OFF no PWM should be measurable. Change FAN Change BMU
What you'll see
If shortcircuit to battery -> PWM 100% -> above 98% FAN goes to OFF state. If FAN cannot be commanded ON too little cooling capacity can be the consequence. Could also be that FAN is faulty ON leading to noise and possibly to much cooling capacity.
System reaction
No direct system reactions.
Diagnostic depth
Detection
Shortcircuit to battery or FAN faulty on PWM above 98% should be translated as OFF request by FAN.
Possible cause
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