My car Audi A3 8P1 TDI 2004

Would anyone be able to advise please; 

I have a problem with both radiator fans they does not come on and air-conditioning is not working. 

What I have done so far is: firstly I have checked with digital multimeter and +12 volt was present on the main plug. 

The air-conditioning fan was working when plugged directly to +12V. When +12V applied to main fan air-conditioning fan does not come on. 

I know for a fact air-conditioning fan should kick in right away and main engine fan should come on when engine temperature raises. 

I was than almost sure that main engine fan is broken as it have control unit inside. I have bought all unit with both fans. Unfortunate fixed and the same problem air-conditioning fan does not kick in but this time i realised after done some driving both fans start working however after I turned ignition off and both fans wont stop. I wait about 40 minutes still running. I was worry it wont stop and drain the battery so I disconnected all unit. I need to mention also that even that both fans start working air-conditioning itself still wasn't working.  

Now the question is should i change temperature sensor ? Thermostat I assume must be good because temperature gauge works fine and the engine is not overheating. 

Is there any other fan control unit ? The only other control unit which I am aware of is Audi comfort module this I think controls more than only fans and is fixed behind air-conditioning control panel inside the car. 

Not sure can I do anything else before going to mechanic and plugging to VAG ? 

 

  

 

 

Sometimes the wiring going to the temperature sensor breaks just by the connector so worth checking that out before replacing the sensor

Welcome to the forum Pawel :) 

sorry to hear your having issues. You'll find the members on here are a friendly and helpful bunch :) 

i would say the sensor is playing up as the temp gauge is working normally. 

cheers

steve 

Thank you, 

Will need to find some free time now to work on the car.  

I will probably purchase new temp sensor anyway before getting my hands dirty :) they are not very expensive.

I am also thinking about buying Xtool VAG401 to be able to do diagnostics. Always want to get one but did not have any major issues so far. 

Now could be useful to sort the radiator-fans and air-conditioning i am sure it will be useful in the future :). 

And still not sure how the main fan is being controlled? Temperature sensor must be connected to control unit which is giving the signals to operate both fans through relay's.

I should probably ask this question in schematics section of the forum but much appreciate if someone could provide with wiring diagrams including connections to control uni. 

Thank you for your support. 

 

Your welcome :) 

glad we could help :) 

i find it's usually sensors that go rather than modules or relays. Sensors can be sensitive (sorry no pun intended). If the relay had failed then in my opinion you wouldn't have the fan working at all. 

Cheers

steve