Radiator fan always on and draining battery

[o-kruse]

Hi all :-)
Have a problem om my 2005 Golf GTI.
After worshop visit changing timingbelt and the startup of the car, Radiator fan is always on and draining battery.
When disconnecting the thick red wire going via 30A fuse to fusebox it stops, of course :-)
Tryed to disconnect battery and measure on red wire going to fan in rsp. to ground, and looks like motor is on all time.
So my conclusion is that relay or whatever electronics in the J293 on the back of the big fan is always closed?
-does anyone have any experience with this?

[muff1991]

i had his on a mk4 golf, turned out to be the fan switch of some sort. and also, check your coolant temperature sensor, as when disconnected, faulty wiring or even a dodgy sensor.. this can cause the fans to activate. although.. should shut off after 10 minutes once the canbus has finished its bit, and yours is staying on.. strange but check all of those in case.

[Dave_M]

I just had same problem although intermittent.  I hooked up VAGCOM which showed an intermittent fault with the signal from the coolant sensor on the radiator outlet - mine’s an Edition 30 so may differ to yours, but on mine that sensor is just below the thermostat housing on the front of the engine, almost directly behind the throttle body.  You need to remove the alternator to get to it.

The ECU measures the temperature difference between that sensor and the one on the near side of the cylinder head - when the difference gets too small the ECU switches on the fan.  However, when it detects a fault with the radiator outlet sensor it runs the fan permanently as it doesn’t know if it needs to or not - hence the issue you’ve got.

On mine it actually turned out to be a broken wire in the loom which I’m in the process of fixing.

Suggest you try to get a fault reader on it though to confirm the issue.

Dave

[Dave_M]

Just re-read your post - are you saying it’s always on even with ignition on?  In which case you’ve got a different problem.....

[o-kruse]

Just re-read your post - are you saying it’s always on even with ignition on?  In which case you’ve got a different problem.....

Hi Dave, sorry I'm new to this postings, so did not find this post again :-)
But here we are..
Yes, it was on all the time, so changed the complete assy with both fans, so seemd to work.
But then intermittent both fans went on an drained the battery after 5 min, once a week or so.
After a while I noticed that this happende generally when I had a short run of max 10 min. and was able to trigger it if I just started the car and turned it off again.
So now is the question, was this something similar to yours?