[jserrano]

Very simple. First clip the wire. The wire end the goes to the cooling fan relay needs to be wired to the center of this switch. The center terminal is labeled COM, which means COMmon. That is to say, when the switch is set to one position called "A" or the second position called "B" the COM terminal will always feed the device you want to control, ie. the cooling fan relays.

If you look at the schematic I've drawn up, in the "A" position the ECU will be in charge of controlling what goes over the COM terminal. In the "B" position, you are in charge of controlling what goes over the COM terminal. Since "B" is attached to ground then you will be providing ground to the COM terminal. That will in turn enable the relays and kick the cooling fans to HI. The cooling fans will be stuck in HI until you decide to flip the switch over to "A" for normal ECU control.

Oh, and by the way, why were you interested in doing this? Any hidden surprises you have for us??

 

[jserrano]

Both fans will always run at the same time and speed. The AC condensor sits in front of the radiator core. Therefore, the fans would also be "cooling" the AC system while running. But when the AC compressor is not running and circulating R134 then there is no affect on the AC system. The AC condensor causes an airflow restriction to the radiator core so removing that will create a more efficient cooling system. Also, if you could somehow get a intercooler mounted in place of the AC condensor then you could toggle your switch manually and that will keep the air charge cooler while entering the intake - a very nice feature for an acceleration run. With a little ingenuity, you could add a pressure sensing switch to sense a boost level and kick the cooling fans ON instead of doing this through manual control.

One final note, whether both fans run at LO or HI speeds depends on what the ECU is sensing. The engine coolant temperature (ECT) sensor, the AC triple-pressure switch, the AC ON switch, and the vehicle speed are what determines how the ECU will control the cooling fans.

 

[jserrano]

drunkmunky: yes, that fan relays are independently controlled. The way you intend to do the splicing should work. Meaning the flexalite fans will come ON whenever the ECU goes to control the LO or HI relays.

 

[jserrano]

i'm so glad i knew you'd come on because you're awesome like that.
my only concern is number 3, due to the fact that the ground line goes back into the relay, and THEN grounds, but due to the splicing, it is also grounding... and going to the chassis is much larger of an attractor than that of going back into the relay..

Thanks for the comments. And you are again correct on pin #3. Whether is gets its ground via the relay or directly from chassis doesn't matter. Good luck with the mod and keep us posted on how everything turns out.