fan controller question

I think the fans are just too high current for any type of PWM setup. I'm not sure why you think you need PWM. On the low speed the fans are pretty quiet. My high speed has never needed to turn on.

I'm running the Dakota Digital Fan controller as is 72blunblu. The reason why this setup works so well with these fans is that it's set to work with the dual speed fans and all the current is handled by the 70A relays, which makes it pretty simple and reliable. The controller just closes the relays through grounding, just like the factory contour computer did.