PWM for fans, will this work?
 

I am wanting to power and control my two Spal fans from my Holley HP ECU via a PWM controller (the Ford Fusion version) and have come up with a plan. I know this has been discussed at length in another post bout I would like to get some opinions as to whether or not this will work. Pictured below is a schematic I have hand drawn and a photo of what I have set up in the input/output of the ECU.

I don't see why not. If I had AC I would use CTS and AC pressure as well.

Andrew

Thank you. Larry

Larry,

I just looked at the schematic again, and I would add a 40amp breaker between the battery 12v+ and the fan controller.

Andrew

Ok, I will. Thanks for your help. Larry

Great time for this question, thanks for posting.

Why do you prefer the ford pwm over the Chevy? Is one that much better than the other?

To the best of my knowledge, they are identical. I avoided the "Corvette tax" by purchasing my Ford Fusion units new off eBay, so my motive in getting the Ford modules was cost.

That said, when I hooked mine up today, including the 40 amp breaker, as soon as I connected the ground wire to the PWM, the fans came on. This is with the cold engine not running and the key off. I cannot yet say it is the fault of the PWM module or a wiring error, more research is necessary.

I hope Andrewb70 will step in here. Larry

UPDATE!!! It works! After I fixed the wires I had inadvertently crossed, it works as advertised. My schematic is good. The fans came on as I had set them up in the input/output section of the ECU. I ran the A/C and it still maintained the prescribed temperature. My thanks to all who offered help and encouragement to me in this project. I will take it our for a freeway cruise soon to give it a real test.

For anyone that may want to do this in the future, do you have the part number for the controller you used?