A3, 2.0, Diese,l 2004 - Cooling fan runs constantly

[Ashraf]

Hi

Got this one in with a cooling fan fault staying ON all the time even if the ignition switch is OFF.

Scanned it and found NO any fault codes

Have booked it in for tomorrow

Did a bit of search here on this forum and found some with same faults but, NO out come of the fix, or may be i have missed some where some thing.

Any idea what could it be or is there any common fault on them, would be a great help.

Thanks Ash

[EndaIRL]

have had this with a few vw's lately. if its not the coolant temp switch (stuck at high temp) its likely to be the module. i think its attached to the fan moter.

[Ashraf]

Hi

Thanks for the reply

Did removed the fan motor and checked it and found all OK But, noticed on the multi plug of the fan there are 4 wires which one is + 12V one - Negative and two small wires which they come from ECU for earth to active the fan, found one of the ECU wire to have continuously earth thats why the fan is ON all the time.

If the coolant Temperature Sensor was stuck at high temp it should have picked the fault code for faulty sensor but, there are NO any fault codes thats what i am not sure if its the ECU faulty or Temperature sensor.

Hope some body might have come a cross some thing like this and would have the idea.

Thanks Ash

[Lockieboy]

Ash, i,m not known for my electrical expertise, but if the wire has a permanent earth, instead of a switched one, could i suggest it has chafed somewhere and earthed out.? Just a thought mate. HTH regards Paul.

[sb126]

With the temp sensor stuck on high temp it does not allways log a code.

I allways check the live data just to confirm the temperature the ECU sees and IR thermometer on the switch to confirm

the real temperature of the sensor

[Ashraf]

Hi

Paul thanks for the reply

First i should say that i am sorry for using the word earth instead of resistance.
its got the switching resistance from the ECU may be this would sound better.

sb126 hi and thanks for the advice i will take a look what live data is reading thats a good point never clicked that in my head thanks for ringing bells

will let you know the out come tomorrow

Thanks Ash

[Ashraf]

Hi

Rite just a quick update on this one checked the live data for cooling temperature before starting at cold start it was 12c.

Started and let it idle till the temperature reached 80c..........Coolant Sensor seems to be working OK.

Any more ideas please welcome


Thanks Ash

[eugene walsh]

Hi Ash

We have had a few of these A3 and mark5 golfs in and it's always ended up being the fan unit.  I think the new one has been modified to stop water from getting into the module.

Hope this helps.

Eug 

[Ashraf]

Hi

OK a quick updates on this one replaced both new fan motors the big fan which has a built in module.
Every thing works fine.  sorted 

Thanks for all the help guys 

Thanks Ash