Radiator and Aircon Fans Not Working

[nigos]

Yesterday in the hot weather I realised that neither my aircon condenser fan or radiator fan are working. I had noticed a few weeks prior that the a/c did not work when the car was at a stand still and just assumed wrongly that it needed a re-gas. However the car decided to overheat whilst stuck in traffic on the M25 yesterday resulting in me calling my break down service. I had already worked out what was wrong even before I lifted the bonnet as clearly there was no problems with a/c and overheating when on the move. Upon opening the bonnet my theory was confirmed. Thinking about it a little further I realised that even in hot weather I had not heard either fan run on after I turned the engine off for a while.

As it happens the break down man who turned up an hour later was pretty clueless, suggesting that the fan only comes on when the temp goes over 90 and the engine overheating could be caused by a faulty a/c pump (I assume he meant the compressor) which is complete rubbish. As we know the a/c condenser fan should always be on when the a/c is on and both fans should be on anyway when the a/c is on. Also how can a fault compressor possibley cause the engine to overheat. Anyways the option given was a tow home or to chance it in the the car. I decided to chance it and made it home fine after having to stop once to cool down.

Now I've just got to work out why the fans don't work. Any ideas??

[martin1810]

Try the engine bay fuse box. SB23 on some models. The fuse may have blown. A faulty intake manifold flap often blows this. If not the then the fan controller has gone and you need new fans.

[nigos]

Try the engine bay fuse box. SB23 on some models. The fuse may have blown. A faulty intake manifold flap often blows this. If not the then the fan controller has gone and you need new fans.

Thanks for the reply. All my engine fuse box fuses start with an F then a number, either way this is irrelevant because I have checked all the fuses now visually and with an ohm meter and they are all fine.

So the safe assumption would be the fan controller then? You say I need new fans, does that mean that the controller is intergral to the fans and housing or that VW will only sell you the whole assembly? Also is it easy to replace? the Haynes manual goes on about placeing the lock carrier assembly in the 'service position' which sounds like a bit of a faff. I am a pretty compentant DIY mechanic as I am an Aircraft Technician by trade so this should be no problem for me right?

Your help on this matter is greatly appreciated...

[martin1810]

The fuse slots say F23 which I guess means fuse 23. The actual fuse is called sb23 and fits in slot F23. If the fuses are ok then the controller has probably gone. Vcds scan may confirm this. I think the only way to get a controller is to replace the whole assembly. Undo four screws and a connector and it lifts out. I doubt you can get it out without moving the front foward as per Haynes guide.

[nigos]

The fuse slots say F23 which I guess means fuse 23. The actual fuse is called sb23 and fits in slot F23. If the fuses are ok then the controller has probably gone. Vcds scan may confirm this. I think the only way to get a controller is to replace the whole assembly. Undo four screws and a connector and it lifts out. I doubt you can get it out without moving the front foward as per Haynes guide.

Fuse is fine so looks like I'm going to be replacing the fans. Will take them off and test with a multimeter first. Unfortunatley I don't have access to VCDS but I really must invest in it. Its getting increasingly hard to troubleshoot and work with out it. It will pay for itself with saved labour costs.

[martin1810]

The fans are probably ok. The controller is usually the problem and I have never seen a part number for it on it's own. It only seems to be available as part of the complete fan assembly. In theory the fans are available on their own but not the bit that fails !!