How are the fans wired ?

[steve-V8s]

Please could someone confirm how the fans are wired. My guess is of the two pairs of cables at the fan connectors the blacks go to ground and the whites are connected to supply via a relay. The relay coil has and active when ignition on supply to one site and the other side is switched to ground by the Otter switch, simple as that.

The circuit I have however shows the live fan feed connected to the ECU ? but the text in Steve’s book suggests that the ECU temperature sensor and the Otter switch are quite independent of each other. Unless the ECU needs to know that the fans are running for some reason and it is an input I can’t believe the drawing is right.

[Johno]

You're correct.

There is a feed from the fan relay to the ECU, or at least there was on mine when I replaced the ECU.

The otter switch and the temp sensor are independent of each other.

The pink or white wires come into the footwell high up on near side behind the glovebox and both go to the fusebox, then there's a feed from that relay into the ECU loom.

The earths go to ground on the earthing point at the front of the chassis which is an utter pig to get too below the rad, but is often a spot that corrodes due to retained water.

I do not knwo why there is a feed to the ECU except for idel correction due to power drain, initiating the stepper motor, but not convinced it would even need to know this.

[steve-V8s]

Thanks for that Johno, I guess the ECU feed is on the fan side of the relay rather than the otter switch side. As you say perhaps it is to give the ECU warning of the extra alternator load at tick over.