I see it is an Old thread but!
I have drawn an example i think is better for you guys!
As you may see, i turned ewerything around, and im switching the GND to the Relay!
This gives a couple of advantages!
*GND is avalable ewerywhere
*If something goes wrong with wire (insulation fault/burnt hole) the Fans Starts instead of blowing the Fuse.
*Less wire to Run equils cleaner installation.
*Easy to hook up more switches to run fan (overheat frotection, EFI, cheap switches threaded into Engine with only ONE wire on it!
It goes like this:
On the +12v supply to relay from Battery i made an dotted line, if you make this Connection Fan will be functioning regardless of Ignition is ON or OFF!
If you choose to conect to Ignition, just do so (+ 12V switched power)
The GND for the Relay is now the switched part!
As you can see there is only ONE Wire out to Ground (less wire is good)
This wire you can connect to the Thermostat control, manual switch inside Car!
Some aftermarket EFI has an Output for Fan, (in my case FAST Ez-EFI)
This ECU goes to GND when activated!
The cheapest temp warning switches with only one wire goes to GND!
On the indicatorlight you can connect that to the same therminal, and oposite side to Illumination wire inDash (you can now controll brightness)
There is NO way of STOPPING the Fan now with Toggle switch!
(Cant see the point in that by the way)
Here is described how to hookup the Ez-EFI