fendervg 33 Posted February 6, 2014 (edited) NOW FIXED. I've had problems with drained batteries and needing jump starts in the last few days, and noticed that the cooling fan seems to run all the time with ignition off (obviously until the battery is empty!) whereas before it was just the after run. Does anyone have any troubleshooting tips? I'll have a read of the definitive cooling thread, and at the moment have the battery disconnected and will check all connections to the coolant senders and fan switch. Cheers for any help. Edited February 18, 2014 by fendervg Quote Share this post Link to post Share on other sites
robrado974 1 Posted February 6, 2014 I would say the sensor is faulty , I had similar problems , in traffic in the summer the fans would kick in as they should . But they kept on running even when travelling at speed when it had obviously cooled down , the only way I could stop the fans was to turn off the ignition and fire the car up again . Rob Quote Share this post Link to post Share on other sites
Jim 2 Posted February 6, 2014 I guess the first / quickest test would be to simply disconnect the radiator fan switch and see if it switches off when it's running (though obviously be careful as you do need to get fairly close to the fans to do this!) If the fans turn off then there's a good chance you just need to replace the rad fan switch :) Quote Share this post Link to post Share on other sites
Simon vr6 10 Posted February 6, 2014 I have had the exact same problem and finally got it sorted after a lot of head scratching! I would do as Jim suggested, if that doesn't work the fault that mine had was the air con switch. I dont even had air con! At least if it is the air con switch you wont have to replace it just disconnect it :) Cheers Simon Quote Share this post Link to post Share on other sites
fendervg 33 Posted February 6, 2014 Ok - will check that. When you mean the air con switch do you mean the third coolant sender at the front of the block? Quote Share this post Link to post Share on other sites
davidwort 0 Posted February 7, 2014 I don't know if the VR has a separate fan switch, but the 16v engines have a small switch on the head that earths through the block to run the fan when the under bonnet temps are high regardless of coolant temp, if this shorts the fan will run permanently when the ignition is switched off. Quote Share this post Link to post Share on other sites
fendervg 33 Posted February 7, 2014 I really hope it's not the sensors as I replaced the coolant ones about 6 months ago when I did the thermostat housing and crack pipe, and the radiator fan switch a year before that. Not looking forward to half drowning in coolant again. Quote Share this post Link to post Share on other sites
Jon_vr6 1 Posted February 8, 2014 It could be the wiring though and not the sensors Quote Share this post Link to post Share on other sites
fendervg 33 Posted February 9, 2014 Right - when I disconnect the sender on the front of the block it keeps going. When I disconnect the radiator sender it stops. Faulty sender? Or a short somewhere? Does anybody know where the after-run takes it's power feed from? Is it straight from the battery? Thanks. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted February 10, 2014 The VR has a separate after-run controller with its own fuses. The main rad thermostat switch only operates when the ignition is on. I'd be looking at the faulty after-run controller module myself. Presumably its timer is dead. Quote Share this post Link to post Share on other sites
fendervg 33 Posted February 10, 2014 Thanks dr_mat. I will be replacing the sender first, just in case. Then I'll be looking at the module. Is it this one that I need: http://www.arz-tuning.de/shop/product_info.php/info/p11564_Radiator-Fan-Control-Relais-Module---VW-VR6.html ? Quote Share this post Link to post Share on other sites
dr_mat 0 Posted February 10, 2014 That's the one. Test it by yanking the fuses out when the car is showing the problem... You'll see it's quite easy to find top right of the engine bay. Quote Share this post Link to post Share on other sites
RPoul 10 Posted February 10, 2014 there are tests in the definitive cooling guide that you can do to find out whether its the sender or module. Mine just had this too and it turned out to be the sender. You might want to check fuse 15 in the driver foot well fuse board. Mine blew when the fan started playing up and still is. Don't think there is any connection though Quote Share this post Link to post Share on other sites
fendervg 33 Posted February 11, 2014 Great - it's started snowing here now - with no garage that puts paid to any plans to change the temp sensor today! Quote Share this post Link to post Share on other sites
fendervg 33 Posted February 18, 2014 Managed to get this changed over the weekend - it was the sender that was faulty - now everything runs normally and the after run fan cuts in and thankfully cuts out as expected. The sender I had in it was a low temp one, so not sure if that could affect it. All fixed now anyway, and thanks for all your helpful suggestions. Quote Share this post Link to post Share on other sites
Roger Blassberg 0 Posted February 18, 2014 Which sender?? The yellow 4-pin or the black 2-pin? Having trouble with my fans as well - see separate thread. Thanks RB Quote Share this post Link to post Share on other sites
fendervg 33 Posted February 18, 2014 It was the three pin fan sender in the radiator. Quote Share this post Link to post Share on other sites
