Cooling fan staying on

[Shodi]

Hey people sorry if this has been covered but cant find a solution.

My cooling fans on 8v Mk3 come on when i turn ignition on and then step upto fast speed when engine is running. goes off when car is switched off so not an after run issue i dont think.

Still runs with rad sensor unplugged
Control Module has been changed (Scrappy part) so could still be faulty I know but hope not

So is there anyone out there with same issue with a solution?

A/C model if that helps.

[justalex81]

is the recirc button and the a/c button on when this happens?

[Shodi]

No both off  tried vag com to see if anything came up but cant see nowt

[rubjonny]

disconnect the plug to the temp sensor in the rad to start with. if this solves it then you can be reasonably sure this is the problem. also check your fan controller for water damage, iirc on the mk3 its under the header tank? if so it could have got water in it.

also, look around the inlet for a single pin sensor with a snapped off spade connector. this is the after-run fan switch, the wires from these like to snap off and earth to the engien block, which brings the fan on.  its a black wire

[Shodi]

OK heres the latest, tried TWO replacement modules (thanks to Stevens Volkswagen Dismantlers) on ebay
Still the same problem though   

But I've now discovered this is only staying on if both plugs are in the module, take out the smaller of the two and the fan works fine!!!!

Now if this is only for the AC then I don't see a problem but if this needs to be plugged in for anything else then I still have a problem.

Any ideas or input?