hi i have a 2007 a3 1.9tdi , the previous owner has done a twin electric fan conversion on the radiator.   I am not keen on the way the wiring is done and would like change the wiring and tidy it up more . question is does anyone have a wiring diagram for this . or nos what the  colors of the fan shroud plug are . number 1 is a thick red wire , 2 is a thin black wire , 3 is a thin green wire and 4 is a thick brown wire . any help would be appreciated please.

As much as I can't help you on the wiring. The question formes need to be asked as to.why the previous owner has fitted a twin electric fan setup. 

What about the wiring do you dislike? Is it unsafe, untidy, ugly colours? Being" not keen" on it tells us nothing.

the electric fans are installed , as the car has a upgraded bigger radiator .  The wiring is wired to a toggle switch for the fans , i want to redo the wiring to the original plug that plugged into the old fan shroud.

I can't help with the details of the wiring. Have you looked on line for wiring diagrams? I know I have seen them in the past.

It would be worth checking if the car's original wiring will withstand the extra current resulting from using two fans.

Cliff could be on to something there. Let's face it, no one creates extra work by fitting additional wiring if there's wiring there, unless the old wiring can't take the extra power. 

1 hour ago, cliffcoggin said:

I can't help with the details of the wiring. Have you looked on line for wiring diagrams? I know I have seen them in the past.

It would be worth checking if the car's original wiring will withstand the extra current resulting from using two fans.

The only diagram i could find , with out uploading pictures , quotes the 2 thin wires on the plug being low speed relay . The to thick wires being high speed relay 

7 minutes ago, Steve Q said:

Cliff could be on to something there. Let's face it, no one creates extra work by fitting additional wiring if there's wiring there, unless the old wiring can't take the extra power. 

the original fan shroud was a factory twin fan i assume its one cooling fan the the other works with the AC . i Will be doing full testing etc before anything , just i would prefere the fans to work off the natural plug that the original shroud plugged in to . 

4 hours ago, Dornish4561 said:

the original fan shroud was a factory twin fan i assume its one cooling fan the the other works with the AC . i Will be doing full testing etc before anything , just i would prefere the fans to work off the natural plug that the original shroud plugged in to . 

I fully get where you're coming from and if it can then it's the route I'd definitely take too 🙂