I know I have seen this before in the tech articles but I cant find it now. Im wiring the fans to a switch to turn them on manually and I know you splice into the green/white wire but Id like to see a diagram if anyone has it or can find it. Thanks

 

https://www.thirdgen.org/techbb2/sho...hreadid=170903 <-- currently dead links but may change

https://www.thirdgen.org/newdesign/tech/cool.shtml

"Primary Coolant Fan Turn-On System
Factory Circuit Operation
On TPI engines, the primary fan is controlled by the ECM and A/C head pressure. The ECM grounds the coolant fan circuit when the coolant temperature sensor indicates the temperature is greater than 222° or when the A/C head pressure is greater than 232 psi and the vehicle speed is less than 35 or 40 mph (depending on application). When this circuit is grounded, the fan relay is energized and voltage is applied to the fan. "

If I remember right I used that method and just put in a switch to link the sender wire up to a ground.