Windstar fan wiring
Bob
But it might help to know what ECU you're running, if you have AC, and if you want to run the fans independently or together with 2 speed operation.
I have absolutely never "needed" the big fan to be on. I turn it on when I'm being hard on the car because the trans cooler is mounted in front of it. Also comes in handy for cooldown at the track since the other fan will turn off and I can continue to cool down to help prevent heat soak.
My small fan is set to come on at 185* and go off at 180* and it runs all the time which isn't the best for it. I've had to replace it once. Even with both fans running my operating temp is 205*-210*. These engines seem to like to run a tad warmer than SBCs.
You have 2 choices, run each fan individually, or run both with 2 speed operation. I prefer individually.
Your ecu has 1 output to control fans. Since your thermostat is 195 the factory setpoint is slightly higher. You can tune it to any temp you want. If you put it at 185, it will run constantly, bad idea.
If you have someone reprogram for you, ie eliminate VATS, etc, he can set that temp. In addition, there's another control, generally used for the AC/vent system that can be set to trigger another fan relay at a higher setpoint. You can find the pinouts over at LT1swap.com.
I use the factory setpoint for one fan. I wanted some adjustability for the other, so I used an adjustable controller (Haywire), since I don't have tuning software.
You can also run both fans at low and high speed using the same triggers, but wired differently. If you want that diagram, let me know.



