well after months of geting irritated and writing threads on here and searching and searching and searching and geting NO WHERE. im gona try this again. i have a 16 inch fan with 3 wires, black, red, blue. red being normal speed and blue being high speed. also have a 12 inch fan. it has a black, and blue wire. i want to wire it up, where both fans run on low then when temps get higher the 16 switches to high with the 12 still running . need help with how to wire it up. and what relays i need and where i can get them. i've searched and searched and found a place that has the relays for cheap but i dont have pay pal so cant get em. any help is greatly greatly greatly appreciated. please dont reply telling me to search, ive done searched. and please dont tell me to get ls1 / lt1 fans, i already have these and and gona use them. even if i have to break down and run this on a toggle. thanks in advance

 

If you hook the Black/Black Blue/Blue, and wire together step 1 should be achieved. For step 2 You'll need to hook into a coolant sensor that will tell it to go to high speed when the temp reaches setpoint. On most factory e-fan setups, 1 fan runs under normal operation controlled by the Coolant temp signal to the pcm, the second fan comes on with the A/C also signaled through the pcm. Basically what you need is to tap it in to where the signal comes from or in your case add it. I'm no expert by any means other than a fair knowledge of electrical circuits and control switches mostly for industrial applications. Same basic theory still applies just smaller components.