Heater fan running continuously

[Viz Wizz]

Hi,

The heater fan on my 2000 Allroad is running continuously after I have turned the ignition off. The end result is a flat battery. I tried removing fuse 25 but that has no effect, which I find very strange.

Can anyone suggest why this is happening?

Thanks, Peter

[VAG-Abound]

EDIT: Oops - wrong fan!

[VAG-Abound]

Does fuse 44 stop it?

[Viz Wizz]

Does fuse 44 stop it?

I'm afraid that I don't have fuse 44.

[VAG-Abound]

Which engine is it, and with air con or just blowers?

[Viz Wizz]

Which engine is it, and with air con or just blowers?

It's the 2.7 petrol and has climate control - including air-con. However, after a bump-ette the A/C fan is not fitted and the radiator thing (condenser?) is probably holed. The result is that Econ is always on (to disable the A/C).

[VAG-Abound]

I can't find any diagrams where fuse 25 or 44 wouldn't be likely to cut it off. If you work out which one does (prob ~30A) it might help untangle why.

If you have a multimeter (or car bulb on wires) you could check that the load side of fuse 25 slot is not still at 12V with fuse removed. Unlikely to be, but would at least explain why removing fuse isn't working.

Was anything rewired after the prang?

[Viz Wizz]

I can't find any diagrams where fuse 25 or 44 wouldn't be likely to cut it off. If you work out which one does (prob ~30A) it might help untangle why.

If you have a multimeter (or car bulb on wires) you could check that the load side of fuse 25 slot is not still at 12V with fuse removed. Unlikely to be, but would at least explain why removing fuse isn't working.

Was anything rewired after the prang?

I'll check that when I have a minute or three.

The "prang" was nothing much. A tow hook did for the bumper, which has been replaced. It also bust the A/C fan and probably the condenser(?). Apart from not refitting the fan yet, no wiring changes were made. All I've done to the wiring before that was to fit a feed to a dash cam and to a BT/DAB thingy, which feeds the radio. It was all working perfectly fine until about a week ago.

[Viz Wizz]

Further to my earlier words ...

My mechanic friend has discovered somewhere that if the heater control module (resistor) fails, the fan will run continuously. He's suggested part No 4B0820521 (NLA) might fix it. Does anyone have any thoughts on this?

[Crasher]

The fan controller F126 modules the earth supply to the fan V2, have you tried removing fuse 26, the fan for the display unit E87? If this does not work, remove fuse 25 and use a DMM to check if there is power either side of the fuse with the ignition off.