00 TDI: Radiator fans always on

[nismodrifter]

Just noticed this issue has popped up on my 00 TDI Jetta.

Turn ignition switch to on position -> both rad fans turn on immediately and stay on.

No codes thrown or anything like that.

I'm thinking it could be the aux fan switch (pictured below)

Any tips on how I can exactly pinpoint the issue???

Edit/Update: I disconnected the connection going to the fan switch, both fans remain on

[luunta]

Re: 00 TDI: Radiator fans always on

Poltergeist.

[BaggedGLI]

Re: 00 TDI: Radiator fans always on

Check your fuses, i cant remember exactly which one it is, but i know if you pull it your fans kick on.

[nismodrifter]

Re: 00 TDI: Radiator fans always on

Checked all the related fuses (5,16,25). All are good.

[luunta]

Re: 00 TDI: Radiator fans always on

I know this seems silly, but are they supposed to be linked together on purpose? Is there a temp. gauge somewhere telling it to be on all the time?

[FlyBoy]

Re: 00 TDI: Radiator fans always on

There's a procedure for checking the fan system in the Bentley manual. IIRC on the 2.0L there is a temp sensor on the rad that actuates the fans, separate from the sensor that the ECU reads. Could be the fan control module, big $$. Dunno if its the same on TDI.

The fans on my buddy's Sentra Spec-V used to run a lot so we put a toggle switch in to control when they run. We also replaced the factory fans when we put the turbo in.

[stefan]

Re: 00 TDI: Radiator fans always on

I know this seems silly, but are they supposed to be linked together on purpose? Is there a temp. gauge somewhere telling it to be on all the time?

I think the second one only comes on in overheat or when a/c is on.

[stefan]

Re: 00 TDI: Radiator fans always on

There's a procedure for checking the fan system in the Bentley manual. IIRC on the 2.0L there is a temp sensor on the rad that actuates the fans, separate from the sensor that the ECU reads. Could be the fan control module, big $$. Dunno if its the same on TDI.

The fans on my buddy's Sentra Spec-V used to run a lot so we put a toggle switch in to control when they run. We also replaced the factory fans when we put the turbo in.

You can do a check with the vag-com that will turn on both fans. I've done that on my old tdi.

[nismodrifter]

Re: 00 TDI: Radiator fans always on

Twas the coolant temp sensor. Took only 15 mins and $17 to fix the damn thing after many hrs of diagnosing wtf the prob could be. Then I broke the clip while trying to get it back on. Car sat for another night till I could make it to SCFC in the morning to get a new clip. Bought 2 clips because I knew I would break/lose one....and guess what....I ended up losing the first one somewhere in the engine bay haha.

Finally back on the road and purring like a kitten.

F this POS: