PWM cooling fan(s) control using ECM

[vstol]

I too have read all the posts and have a question. I have a LS3/427 with a reprogramed GM ECM from Blue Print Engines. I just purchased a Dewitt radiator with dual Spal fans. Dewitt says I can not run the fans off the ECM (wire already there from ECM). Not a big deal if I can not but I am not sure why not. Comments? Thanks

[4wheels]

Could you be more specific on what you have (more details)?

What fans do you have from Dewitts. They sell the Spal conventional fans and the DC brushless fans. Control strategy/system is very different depending on which ones you have.

Even with the conventional fans, did they supply the wiring harness? If so how do they have them wires (simple ON/OFF control or High/Low speed using relays more like a earlier GM vehicle).

And then how did Blueprint programming the ECM. What did they expect it to be doing?

And what ECM wiring harness configuration do you have?

Originally Posted by vstol

I too have read all the posts and have a question. I have a LS3/427 with a reprogramed GM ECM from Blue Print Engines. I just purchased a Dewitt radiator with dual Spal fans. Dewitt says I can not run the fans off the ECM (wire already there from ECM). Not a big deal if I can not but I am not sure why not. Comments? Thanks

[vstol]

Originally Posted by 4wheels

Could you be more specific on what you have (more details)?

What fans do you have from Dewitts. They sell the Spal conventional fans and the DC brushless fans. Control strategy/system is very different depending on which ones you have.

Even with the conventional fans, did they supply the wiring harness? If so how do they have them wires (simple ON/OFF control or High/Low speed using relays more like a earlier GM vehicle).

And then how did Blueprint programming the ECM. What did they expect it to be doing?

And what ECM wiring harness configuration do you have?

I will get the exact specs but the relays and harness for the dual Spal fans are included with basically a on off switch at 195/175. The ECM for the engine is a GM setup with the power wire from the ECM to the fans. I would think it would work since it would send the power when the temp was reached on the engine. Thanks