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Matt J
Matt J, ASE Certified Technician
Category: VW
Satisfied Customers: 1399
Experience:  Automotive Warranty Claim Administrator for VW Extended Warranty
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Volkswagen Passat Cooling fan will not shut off - stays on

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Cooling fan will not shut off - stays on intermittently for hours after engine is off. VW Passat 2002 1.8T. I've tried removing relays 370 and 373 while the engine is off with the fan running -- this didn't shut off the fan. The fan appear to be located in the right front section of the engine compartment -- near air filter. Needless to say this drains the battery overnight.The fan will turn on every 3 minutes or so and run for a few minutes -- for hours. Could this be a radiator sensor switch?

Matt J :

Hello my name is XXXXX XXXXX I will be more than happy to assist you

Matt J :

In the picture below are the cooling fan relays remove these relays and see if the fan stops. If the picture is not the same as your relay box let me know. There are two different ones.

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JACUSTOMER-6u5j13gf- :

Thanks Matt -- I'll try it in a few hours when I get home. I appreciate your help. I've also seen references to a "Radiator Fan Control Unit" which is $250+ and a Radiator sensor switch. Do either of these sound like potentials? I may not get back to this post till tomorrow. Tim

Matt J :

Before you remove the relays unplug the Cooling fan temp sensor switch. To do this you will need to get under the vehicle, on the drivers side of the radiator where the radiator hose connects there is a sensor connected to the hose. Unplug it and see if the fans stop running. If it does then that sensor is bad. If the unpluging the switch does not stop the fans then yes the Radiator Fan Control Unit is the problem.

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JACUSTOMER-6u5j13gf- :

Matt, I think I need the other relay diagram. I looked at the relay bank that's in the back -- I saw another relay labeled 370 (same as a relay in the front bank). I removed it -- fan still didn't shut off. I removed the batt cable overnight -- otherwise it would be dead.

JACUSTOMER-6u5j13gf- :

Some more info on the fan running, this is a typical pattern: Run for 3 minutes, off for 5 minutes, run for 4 seconds, off for 3 minutes, run for 2 minutes, etc. till the battery is dead over a span of several hours. I'd like to get you paid -- can you answer these items? then I call it done: (1) Provide the other relay diagram, (2) Approx location of the "Radiator Fan Control Unit" (3) any other last thoughts on what I should look for? Thanks a bunch Matt!

JACUSTOMER-6u5j13gf- :

BTW, I did locate the temp sensor switch -- didn't get it removed -- will need to put the car on ramps to get under it sufficiently.

Matt J :

Sorry for the delay. My main computer is down and my back up is not updated like my main comouter.

Matt J :

It will take me a few min to load everything up

Matt J :

So you have that Relay Block under the dash. That relay block has the Cooling Fan Relays in it. The cooling Fan Relays are in Slot 5 214 and Slot 8 213. Relay 370 and 373 are not the correct relays.

Matt J :

Here is the location of the module but it is actually called Coolant Fan Control (FC) Series Resistance, I have a feeling the sensor will be the cause.

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Matt J :

If you have any questions or need more info please let me know.

JACUSTOMER-6u5j13gf- :

Thanks Matt -- really appreciate your help. That covers everything I think I need. Accepting/providing positive feedback.

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