Dodge Repair Questions? Ask a Mechanic for Answers ASAP
Hi my name is ***** ***** I'll help you with the minivan AC.
The vibration that you describe sounds like the cooling fan motor. When the AC is turned on the click that you hear is the AC compressor clutch engaging to turn the compressor. This is normal. The cooling fan is driven to a high speed when the AC is turned on to keep the condenser cool. The vibration is likely due to the cooling fan motor going bad and having a slight imbalance in the electric motor winding. When you turn the AC off the noise goes away because the fan speed is slowed down which is a different frequency. To fix the issue you will need a new radiator cooling fan.
picture of cooling fans
There are two fans. One is the low speed fan and the other is the high speed that comes on with the AC turned on.
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