I have a polo rad and the fan kicks in automatically. I also have a savage fan switch which only illuminates, pretty pointless having of fitted but I didn't build the car. How is an override wired in?

you just need to wire the switch in parallel to the thermostatic switch, that way the relay can be powered by either

Assuming it's currently (no pun intended) switched on by the R1 ECU...

You just need to use the savage to switch on a fused 12v feed to the blue wire into the fan.

adrian

yeah i am pretty sure its the ECU bringing on the fan, just shy of 100 degrees it come son in traffic.