Cooling fan running constantly!

[brady88]

Asking for advice on behalf of a work colleague. His cooling fan comes straight on from startup and never goes off... even in winter meaning his car takes forever to heat up :(

Anyone else had the same problem?... found a solution?

Cheers!

[doylebros]

Check to see if anyone local to you has a VCDS  allowing a vehicle scan :-

http://www.mk5golfgti.co.uk/forum/index.php/topic,120.0.html

This will show if a temperature sensor has failed etc.

[brady88]

I've got a vag-com but it isn't showing any faults to do with the cooling/ engine etc... just one for the stereo module being incorrectly coded.

It was in for a service at the weekend and they couldn't pickup any faults either :/ ...struggling for ideas!?

I've suggested replacing the coolant temperature sensor, it's only £5 so worth a shot! ;)

[doylebros]

Use the measuring block facility to watch the temperature values change with your VCDS tool!

[brady88]

Use the measuring block facility to watch the temperature values change with your VCDS tool!

With a Micro-can??... where do I find that facility? lol

[doylebros]

Never used a micro can but should be the same

http://www.ross-tech.com/vag-com/m_blocks/

http://www.ross-tech.com/vag-com/m_blocks/130-137.html

These links show the area to look at see if you understand it - if not come back.

[brady88]

It's doesn't really tell you how to access the facility through VCDS though... plus only certain control modules are accessible with the Micro-can... I'm running a scan just now to try and install some extra modules.

[doylebros]

Watch this :-

http://m.youtube.com/watch?feature=related&v=NlGq8cgmqLY

Then you want to move through the blocks until you find cooling temp and see the reading change as the engine runs first.

Then look at group 130 to 137 see if anything looks odd and you'll be able to check the items in output test.

[brady88]

Watch this :-

http://m.youtube.com/watch?feature=related&v=NlGq8cgmqLY

Then you want to move through the blocks until you find cooling temp and see the reading change as the engine runs first.

Then look at group 130 to 137 see if anything looks odd and you'll be able to check the items in output test.

Tidy mate cheers :) ...that's actually a really good quick tutorial.

Will try it on his car tomorrow and see what I can pick up... I suspect all it will show though is the car taking an age to heat up... or will it show the coolant being too hot to start with if there's a faulty temp sensor?

[Sie]

Doubt it is temp sensor, it will be the small fan, the resistors go in them like the old mk4 ones used to go. Needs changing will either be a tremic or Siemens, make sure you replace it with the same one. If you turn your air con off it should stop.

Simon

[brady88]

Doubt it is temp sensor, it will be the small fan, the resistors go in them like the old mk4 ones used to go. Needs changing will either be a tremic or Siemens, make sure you replace it with the same one. If you turn your air con off it should stop.

Simon

It's the larger fan that's running continuously... even with the air-con off it continues to spin.
Is this due to the failure of the smaller fan?... to be honest I wasn't under the bonnet to notice if the smaller one came on.

[doylebros]

I do agree with Simon but that can be checked in the HVAC MODULE - output test will check both fans as part of the test if I remember correctly.

Best to use the tool you've bought too identify the fault and remove the guesswork.

[brady88]

I do agree with Simon but that can be checked in the HVAC MODULE - output test will check both fans as part of the test if I remember correctly.

Best to use the tool you've bought too identify the fault and remove the guesswork.

Had a look through every single output module (over 150) and there's no mention specifically of the fan(s)... I'll see if his temp is reading hot from startup and take it from there ;)

[doylebros]

From your other thread photo go into module 08 - output testes and you'll see how to test the climate system which will run both fans etc.

[brady88]

From your other thread photo go into module 08 - output testes and you'll see how to test the climate system which will run both fans etc.

Right that's the plan then... I ran it on mine but I don't have the fan issue, so all I got was "refrigerant level low" which is pretty obvious anyway as the air-con is doing F-all ha! Needs a top-up :)

Also got an intermittent boost fault which I'm guessing is a failed diaphragm DV after stage 1 map... got a new piston DV to replace it anyway. See how that goes!