PWM cooling fan(s) control using ECM

[65 Drop Top]

I’ve read through this entire thread, more than once, and I think I’ve retained most of the information. But, what I don’t completely understand is how to make multiple systems work together, for example: GMPP crate engine controller, VA trinary switch, DCC PWM, Dual Spal fans. Does anybody have a wiring diagram for this combination that they could post? Seems like this is popular combination of parts. And a follow up question would be if somebody used a Speartech or PSI harness instead of GMPP would that change anything? Thanks

[dhutton]

When you use the DCC fan controller it is completely standalone and not connected to the ECM. The DCC instructions tell you how to interface to the trinary switch. It’s pretty straightforward. The fans connect to the DCC controller. The ECM fan relays are not used.

Don

[waynieZ]

Have you used one of the DCC controllers Don ? Did it work well?

[dhutton]

Originally Posted by waynieZ

Have you used one of the DCC controllers Don ? Did it work well?

I have used it a couple of times. Works great.

Don

[65 Drop Top]

Originally Posted by dhutton

When you use the DCC fan controller it is completely standalone and not connected to the ECM. The DCC instructions tell you how to interface to the trinary switch. It’s pretty straightforward. The fans connect to the DCC controller. The ECM fan relays are not used.

Don

Got it, thank you. What I didn’t realize was that the DCC and the GMPP ECM do not hook up together. Are there any potential issues if the ECM does not know what the fans are doing? And then do you just abandon the GMPP fan wire?

[dhutton]

Originally Posted by 65 Drop Top

Got it, thank you. What I didn’t realize was that the DCC and the GMPP ECM do not hook up together. Are there any potential issues if the ECM does not know what the fans are doing? And then do you just abandon the GMPP fan wire?

I just left the GMPP fan wire unused. No issues. ECM only cares about coolant temperature.

Don

[214Chevy]

Thanks for all of your insight Don.

[NAPA 68]

Looking at the DCC controller and reading the instructions, it appears to me the fan will continue to run after the car is shut off. First, am I correct? Secondly, is there a right way to get around it?

In advance, thanks for your consideration.
Tim

[dhutton]

Originally Posted by NAPA 68

Looking at the DCC controller and reading the instructions, it appears to me the fan will continue to run after the car is shut off. First, am I correct? Secondly, is there a right way to get around it?

In advance, thanks for your consideration.
Tim

It only runs for a few seconds until the coolant in the radiator falls below the set temperature. Not a big deal in my experience.

Don