PWM cooling fan(s) control using ECM

[GregWeld]

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.


https://www.youtube.com/watch?v=CZ1ihcmsoo0


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.

[erick_e]

Originally Posted by GregWeld

Thanks. I wasn't sure how to insert YouTube videos. I tried the standard [YT] but it didn't work. I updated the post.