Need to rewire some aftermarket two wire fans up. I am running a microtech ecu and trying to use as much of the stock wiring harness as I can to save running new wires unnecessarily. I am part way there with what I need to do but not Sure on a couple of things and hope someone can help.
I managed to run a thermoswitch plug and pick up the original harness plug under the dash. So have found that at the solenoid. Now with two fans must I run each fan off it's own relay? Seems like it from most schematics I can find? But why? Is that to not over load the solenoid? Also, does it matter if the solenoid is completing a live circuit or earth? I can see the no.3 solenoid completes the earth for one speed of the stock fans and it looks like the no.1 completes a live to feed the other speed? So I could use either relay 1 or 3 to power both fans with a little switch on some wiring. Or if I need a relay per fan I might need to use both or one of the others as well. Either way I think I need to loop a ground or a live somewhere to get the necessary earth and live feeds.
Mainly I just need to know how many relays I require at minimum and I can probably figure the rest!
Thank you
Lee