W140 Aux Fans will not turn OFF

[jcowens2000]

Hi,

1995 S420

I have an unusual problem. My auxilliary fans (2 fans at front of the car) will not turn off. From the moment the car is turned on, both fans run at maximum speed regardless of AC and engine temperature.

Any suggestions?

Thanks in advance,
JC

[Educaid]

This happened to my 1989 260E. After $500 of charges by the dealership, they told me it was the water temperature sensor -- a $35 part. Fixed the problem. Still can't figure out why their diagnostic scanner could not determine the real cause as this seems to be one of the codes.

[Arthur Dalton]

Before anything, check the connector at the temp sensor for a good contact... if there is a poor contact here , the system defaults into full fan to prevent overheating if the sensor/connector fails.