just about to wire my thermo fans up, noticed 1 has 2 wires (black and blue) and the other has 3 wires (blue green and black) what is the third wire for? all 3 wires are the same guage, the fan came out of a little 80s hatch (barina/swift i think). i dont really feel like frying the motor by wiring incorrectly, so what is the 3rd wire for anyone?

test it out on a battery, you wont fry it out doing that,

im guessing there is an earth, power and the third is from the ecu temp sender which signals when it gets over 80°c for example

cool, well the blue and black seem to work, so i will leave the green alone for now. very happy to say the water system seems to be just about sorted finally. managed to get all of the bubbles out in the last couple of days, had her running for about 15min straight saturday with no fans, until the whole water system heated right up and the temps started to creep higher then Id like. hooked the fans up to a manual switch today to test, turned them on when the thermostat opened (at 80deg) and she ran for 15 min or so bouncing between 77 and 82deg. which i am very happy about, will be exciting to take it down the road when the scoops are over the rads and see how it goes.
i just have one more question. i nicked my thermoswitch and housing from a saab (9000?), it is basically about 10cm of steel tubing made to fit inline with the water system, with a big thermoswitch screwed into the side, the thing is, the switch has 2 connectors on it. i have assumed one acts as the ground, the other goes to the relay for the fan. when i hook it up like this the fans come on with the ignition, my previous setup, when the thermoswitch broke the fans just didnt come on, i am assuming that with this switch it defaults to on when it fails as a safety precaution, and this is why my fans are coming on? hope these switches arent too hard to find and buy!

tis soo cool, if i hook the fans up direct, when i turn the ignition on it sounds like a hovercraft LOL

It's not a twin speed fan is it? That could be what the 3rd wire is for

its probably the same one then as in my zook it has 2 speeds one for when the a/c cuts in and one for just cooling the rad

i put a new fan in a mates nissan micra a few weeks ago and the new one i got had 4 wires unlike the old one which only had 2
think it was the same deal just 2 speed

-Joel