ALH Jetta fans wont turn off at all

**UPDATE** so what ended up being the problem is that one of the wires going into the plug for the FCM actually came of the pin within the connector so once that was fixed now the fans work as they should







I have mk4 jetta alh tdi and my issue is that the radiator fans wont turn off even after the car has shut off with the key out of the ignition.


i have replaced the fuse box on top of the battery along with the cable the goes to the alternator and the one that goes to the stater


the car has also had 3 different fan control modules in it and still having the same problem


i have tried to unplug everything temperature sensor under the hood one at a time to see if the fans stop and i got nothing from that either


any advice would be greatly appreciated thank you

What brand and where did you get the modules from. The only good ones worth buying are the ridiculous priced genuine OEM ones, not the ebay or amazon or box store crap. All the reviews here and on these sites all say the same issue you do, that there garbage. There is only 1 thing that starts and stops the fans, that module other than the things you just unplugged, so there isn't much else, unless I'm missing something, your due for a 4th, sigh

Mongler98 said:

What brand and where did you get the modules from. The only good ones worth buying are the ridiculous priced genuine OEM ones, not the ebay or amazon or box store crap. All the reviews here and on these sites all say the same issue you do, that there garbage. There is only 1 thing that starts and stops the fans, that module other than the things you just unplugged, so there isn't much else, unless I'm missing something, your due for a 4th, sigh

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they where all oem ones i got from other cars

Have you checked your fuses in the dash fuse block? Also read on another forum that a guy needed a new harness due to coolant intrusion.

On the gasser VWs I think it's 16, not sure on the TDIs

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WildChild80 said:

Have you checked your fuses in the dash fuse block? Also read on another forum that a guy needed a new harness due to coolant intrusion.

On the gasser VWs I think it's 16, not sure on the TDIs

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i tried changing out the #16 fuse with another one but still nothing changed

check all these fuses..

To ensure the AC circuits and the Fan Control Module has power check:
Fuse 5 on the cabin fuse panel.
Fuse 16 on the cabin fuse panel. When this fuse is blown the radiator fans
will often run unexpectedly.
Fuse 25 on the cabin fuse panel.

the temp sensor on the back of the block does not control these, on the lower side of the ride, drivers side, there is a temperature sensor that talks to the FCM, check this to see if shorted or something maybe

steve6 said:

check all these fuses..

To ensure the AC circuits and the Fan Control Module has power check:
Fuse 5 on the cabin fuse panel.
Fuse 16 on the cabin fuse panel. When this fuse is blown the radiator fans
will often run unexpectedly.
Fuse 25 on the cabin fuse panel.

the temp sensor on the back of the block does not control these, on the lower side of the ride, drivers side, there is a temperature sensor that talks to the FCM, check this to see if shorted or something maybe

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i already tired unpluging the temp sensor on the bottom side of the rad on the drivers side and fans did not turn off after i unplugged it



but i will double check all those fuses



thanks for the info

About three months ago, I installed an eBay FCM on a 2001 New Beetle to address the same issue........ fans running constantly. Problem was solved with the new FCM.

Based on what you've already done, the only other thing I can think of would be a faulty AC button there on the dash. But, it should also cause the AC compressor to engage. And, if the in dash fan is turned off, those should shut-down, assuming it is a faulty AC button... (which I doubt)

AndyBees said:

About three months ago, I installed an eBay FCM on a 2001 New Beetle to address the same issue........ fans running constantly. Problem was solved with the new FCM.

Based on what you've already done, the only other thing I can think of would be a faulty AC button there on the dash. But, it should also cause the AC compressor to engage. And, if the in dash fan is turned off, those should shut-down, assuming it is a faulty AC button... (which I doubt)

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well the ac compressor clutch doesn't engage when i turn on the ac i thought i just needed a ac compressor



do the ac compressor and fans both work on the FCM?


i recently purchased the car and the ac wasnt working when i got it

From Bently directions, paraphrased:
Locate the radiator coolant switch, driver's side low down on the
radiator, dislocate the plug, and using a fused jumper wire, close pins 1 and 2; both fans should run low speed. Then try closing pins 2 and 3; both fans should run on high.
If the tests fail, replace the switch. Yours sounds dead though.

do the ac compressor and fans both work on the FCM?
No, pretty sure the A/C clutch is activated/deactivate by the thermal cutout switch (F163). -Driver's side upper radiator hose where the split
is located.

STDOUBT said:

From Bently directions, paraphrased:
Locate the radiator coolant switch, driver's side low down on the
radiator, dislocate the plug, and using a fused jumper wire, close pins 1 and 2; both fans should run low speed. Then try closing pins 2 and 3; both fans should run on high.
If the tests fail, replace the switch. Yours sounds dead though.

do the ac compressor and fans both work on the FCM?
No, pretty sure the A/C clutch is activated/deactivate by the thermal cutout switch (F163). -Driver's side upper radiator hose where the split
is located.

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Defiantly give that a try thank you so much for the Info much appreciated

bigboost3 said:

i already tired unpluging the temp sensor on the bottom side of the rad on the drivers side and fans did turn off after i unplugged it

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Your radiator temp switch is shorted; that's a direct signal to the FCM and, since you unplugged it and the fans shut down, assuming the rad was not hot it's bad.

Genesis and STDOUBT got this, if it's not that radiator sensor/switch it has to be the ebay part.

Genesis said:

Your radiator temp switch is shorted; that's a direct signal to the FCM and, since you unplugged it and the fans shut down, assuming the rad was not hot it's bad.

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that the thing i did unplug the temp switch on the radiator and the fans still did not shut down

bigboost3 said:

that the thing i did unplug the temp switch on the radiator and the fans still did not shut down

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I thought your previous post said when you unplugged the switch they DID shut down. If I got that wrong then disregard.

Genesis said:

I thought your previous post said when you unplugged the switch they DID shut down. If I got that wrong then disregard.

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no worries thank you for the info

update found problem

The solution-

bigboost3 said:

**UPDATE** so what ended up being the problem is that one of the wires going into the plug for the FCM actually came of the pin within the connector so once that was fixed now the fans work as they should<<<<<<<<<<<<snip>>>>>>>>>>>>

Click to expand...