Depending on which Spal fans you have you, you might be able to use one C6 fan controller for both. If the combined amp draw of both fans exceeds 32 amps, you will need two C6 fan controllers.

By the time you get two controllers (unless you want to go junk car hunting...the Ford Fusion used the same controller) you might be better off selling the fans you have and going with the new brushless fans.

The C7 fan should fit a Chevelle radiator size well or perhaps the Chevrolet Volt dual 12" setup. The new fans have the controllers built in. I have several customers using the C7 fan and Holley EFI. The C7 fan is 600 watts and the Volt fans are 300 watts each.

I plan on updating the GTO this spring and will likely use the Volt fans.

Andrew

Thanks Andrew. My plan was to use the PWM controller that Northern Radiator sells with development from Carl at Vaporworx. It will work with everything I already have. Do love the idea of PWM fan control, wish that Holley had it built into their ECU; they have controls for nearly everything else lol.

Carl's controller is a standalone unit and so it doesn't need anything from the Holley EFI.

Correct.

Correct. I was hoping that the Holley could do it, but if I have to buy a controller and possibly change fans it's easier to use Carls setup.

So after re-reading all 58 pages of this thread is there a consensus on if a late (2019-20) version GMPP connect & cruise E67 will work ? The last failed or maybe frustrating is a better term, efforts were back in 2017 if memory serves.

Has anyone had success lately? And if so, what was the fix? Other than of course sourcing a junkyard E67?

Thanks
Mike

So touching on the whole E67 GMPP ECM's being unable to run PWM fans, is this specific to that older version of the ECM? (12636660)

My ECU is GM PN 19354333, does anyone know if they made revisions to the software that now allows PWM control of the fans?

I never attempted it again. Even with on/off fan control I have been using Dakota Digital controllers instead of the ECU as the existing strategy in the ECU is so colossally dumb and cannot be changed.

Current (2021) GMPP E92 PWM possible or not?
 

So, this is a very long thread, but a question that still isn't clear to me is whether a current GM LT4 Crate harness with E92 can support PWM? It appears that only fan relay control is provided (from instruction manuals). Can a PWM signal be pirated off the harness for SPAL brushless fan control somehow? :)

Andrew, is this not the same as what you did with my Term X and my Spal brushless? Or something completely different and I should delete this.. lol