While stuck in traffic yesterday for around 45 minutes the temperature gauge hit the end stops and the DIS was showing 'COOLANT'.

I turned the climate up to MAX and the fan on full and slowly the temperature came down to its 'usual ' place on the gauge - and stayed there until the traffic started moving again.

So today, I left the car idling and sure enough after 45 mins the car overheated but the large (LHS) fan would run very slowly for around 10 seconds and then stop - It would do this every 2 minutes - I measured a voltage of 2.2V while it was running.

After letting the car cool down I set about fault finding - The 2 lots of 12V and ground were present on the large 4 pin connector that leads to the fan control unit. I had continuity from the ECU to the fan control unit.

I cannot get the fans to run even using VCDS to to activate the cooling fans under OUTPUT TEST. If I disconnect the coolant temperature sensor and bridge the plug with a 30 Ohm resistor, the car thinks its temperature is 100 degrees - but the fans will still not kick in.

There are no fault codes showing in VCDS.

The fan control unit (J293) was changed 3 years ago due to the fact it was blowing the 60A fuse!! - I suppose it could be faulty, but I would expect a code.

52 minutes ago, QuattroMark said:

While stuck in traffic yesterday for around 45 minutes the temperature gauge hit the end stops and the DIS was showing 'COOLANT'.

I turned the climate up to MAX and the fan on full and slowly the temperature came down to its 'usual ' place on the gauge - and stayed there until the traffic started moving again.

So today, I left the car idling and sure enough after 45 mins the car overheated but the large (LHS) fan would run very slowly for around 10 seconds and then stop - It would do this every 2 minutes - I measured a voltage of 2.2V while it was running.

After letting the car cool down I set about fault finding - The 2 lots of 12V and ground were present on the large 4 pin connector that leads to the fan control unit. I had continuity from the ECU to the fan control unit.

I cannot get the fans to run even using VCDS to to activate the cooling fans under OUTPUT TEST. If I disconnect the coolant temperature sensor and bridge the plug with a 30 Ohm resistor, the car thinks its temperature is 100 degrees - but the fans will still not kick in.

There are no fault codes showing in VCDS.

The fan control unit (J293) was changed 3 years ago due to the fact it was blowing the 60A fuse!! - I suppose it could be faulty, but I would expect a code.

Hi not necessarily I think your fan motors are on the way out, brushes probably and if you look at the age of the car they have not done badly, would suggest a new fan pack.

Steve.

I did think that it could be the motors - but why is there only 2.2 V on the LHS fan and nothing on the RHS - I ran out of time today but maybe tomorrow I will take the whole fan tray out and test each motor with a 12V supply.

2 minutes ago, QuattroMark said:

I did think that it could be the motors - but why is there only 2.2 V on the LHS fan and nothing on the RHS - I ran out of time today but maybe tomorrow I will take the whole fan tray out and test each motor with a 12V supply.

Hi I really wouldn't bother because I have very little faith in that being the answer, as in they are repairable, there is no way to get the internal parts you would require and times effort and expense its better to replace them when you consider how cheap aftermarket packs are,

Steve.

Well this has turned into a double whammy!

Got the fan pack off - the small fan does not work with an external PSU - the large fan however does work with an external PSU........which means the control unit is faulty.......

OK - so figure this out......

New small fan fitted and spins when connected to 12V as does original big fan.

New fan control module fitted - still have the same issue, fans don't work.

Even after using a 100 ohm resistor instead of the water temp sender to give a temp of 120 degrees (coolant warning on DIS) fans still do not spin.

I can get them to spin, albeit very slowly, by activating OUTPUT TEST in VCDS.