PWM cooling fan(s) control using ECM

[dontlifttoshift]

Andrew, bolding mine.

Originally Posted by erick_e

Well, I finally got around to testing my theory about the brushless fans working with the factory ECM.

Bottom line, the factory ECU can control these fans. Since I had already replaced by previously burnt up fan connector I was able to quickly connect the brushless fan to my car with another connector. Its just as simple as connecting the B+, B-, and PWN wires together. The factory ECM commands 128Hz, and the brushless fan is recommended for 100Hz. SPAL tech support says 128 should be OK, but 100Hz would be optimal. This can easily be changed with HPTuners or EFI Live. Changing the PWM type was not required. PWM Electric is what is required, not PWM EV like the C7 Corvette.

Once connected I fired up the Tech2 and commanded the fan on. Below you see it running at 90% duty cycle. I had the fan facing down to create restricted airflow (to simulate radiator, condenser and
heat exchanger). Notice it only dropped .3v at 90%. Not bad considering the vehicle wasn't even running.



I didn't have time to test fit Dewitt's fan shroud with my EForce. Hopefully it fits, it's a beautiful shroud. But if it doesn't fit I might be able to make the brushless fan work with the original shroud with an adapter. The fan blade is the same dimension as the OEM blade, but the motor is a little smaller in diameter. I'll cross that bridge when I have to, if I have to. Hopefully the Dewitt's shroud doesn't interfere with my coolant lines and I don't have to.

[andrewb70]

Thanks Donny!

I follow this thread closely, but somehow I missed that video!

Looks like those new Spal fans with the controller built in would be easy with the Dominator! I am always looking for cool, new stuff for future builds!

Andrew

[stan65]

Anyone know what PWM voltage the ECM is outputting? 5v, 12v?

Thinking I may tackle it as an arduino project as I have GMPP LT4 controller.

Stan

[LonnieJ]

Originally Posted by stan65

Anyone know what PWM voltage the ECM is outputting? 5v, 12v?

Stan

I'm definitely not an expert, but from my countless hours researching I believe it is 5V

Lonnie

[andrewb70]

Originally Posted by stan65

Anyone know what PWM voltage the ECM is outputting? 5v, 12v?

Thinking I may tackle it as an arduino project as I have GMPP LT4 controller.

Stan

Stan,

It is PWM- so it is pulsing to ground.

Andrew

[LonnieJ]

Thanks Andrew for setting me straight! You have forgotten more on this subject than I'll probably ever know The 5V most be the a/c pressure sensor?

[dhutton]

The voltage swing of the active low PWM signal would be determined by the voltage the pull-up resistor etc is connected to. If you connect it to 12 volts you will get a 12 volt signal.

Don

[jmac]

Wow, what a great thread with a wealth of knowledge from multiple contributors!

I'm very intrigued by this.

From what I've read, can you use the Spal brushless fans alone with PWM control without having to use the controller from the C6 or Ford Fusion?

I'm referring to post #445 from Blake-B.

Is the controller built in to the fan motor?

Thanks!

[samckitt]

A few people have asked me if I had any more of the connector kits for the Corvette PWM module. In the past I had kits that is the connector body, 4 large high amp terminals & seals, a small terminal & seal for the signal, & some blank plugs for the open holes. I am trying to get all the parts for the other connector that is 2 high amp terminals & one small terminal so the fan assy can be easily removed if needed.

If I was to order more to make these kits, who would be interested in them and would you want all mentioned above, or just the connector for the module itself?

Not sure yet what price would be until I find out what they are charging me. In the past I sold them for $50 shipped for the module connector kit alone. I probably can do it for less if enough ordered.



Trying to find both sides of this connector too:

[eville]

Originally Posted by samckitt

Trying to find both sides of this connector too:

Sam, I think this is what you're looking for: https://www.amazon.com/replacement-C...teway&sr=8-130
https://www.amazon.com/Replacement-C...ateway&sr=8-49