Strange fan problem

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Muhammedman
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Registered for: 8 years 7 months
Location: South Africa

Strange fan problem

Post by Muhammedman »

Hi guys 

I have a jetta 5 2.0fsi with a strange issue thats only started very recently...
The electric fans turn on at full speed a few minutes after turning off the engine and they run till the battery dies.
When switching the ignition on, they turn off.
The fans also operate as normal when the engine is running. 

Diagnostics don't reveal any faults.
I've replaced the 2 temperature switches but this hasn't changed anything.

Not sure what else to check... any ideas ?
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Belix
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Car Make: VW
Car Model: Passat B8
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Location: Randburg

Re: Strange fan problem

Post by Belix »

Do you have anyone that can give the car a scan with VCDS or similar?
Muhammedman
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Posts: 3
Registered for: 8 years 7 months
Location: South Africa

Re: Strange fan problem

Post by Muhammedman »

I've scanned it with delphi and no errors coming up.
Someone's told me that the fan itself could be the problem. i don't want to end throwing money at the problem replacing parts. Would prefer to find the actual issue.

Maybe I need to check with an auto electrician.
Callum229
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Car Make: VW
Car Model: Jetta MK5 TDI DSG Highline
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Re: Strange fan problem

Post by Callum229 »

This is a common issue, when the fans are running after the engine is off, is either due to overheating or faulty temperature sensor or relay sticking/wiring issue.

You can test the fans via VCDS and check that the fans switch off and on and are ramping up and down, this will eliminate the relay or wiring from being faulty.

If that checks out, I would suspect the coolant sensor that is on the radiator is faulty, a wiring issue or it is the wrong spec since you have replaced it, you can use VCDS to check the sensor temp and compare it to the sensor in the head of the engine and check for temperature irregularities. The fans come on when temp goes over 90 degrees, I can't remember how much but I think it comes on at 93 degrees or 95.

Hope it is something simple.
2007 VW Jetta MK5 1.9 TDI DSG,

Mods: Simple EGR delete, LED interior set up, LED rear footwell lights, LED Puddle lamps, LED Doorhandle illumination, LED License plate lights, LED Boot lighting.

2007 VW Golf 5 1.9 TDI DSG, no mods.

2007 VW Transporter 2.5 TDI 4motion, no mods.
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