Genv Gm pwm fans radiator (cbr/spal)


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-2018 Chevy Colorado uses same fan motor as camaro (possibly silverado etc)
- Colorado oem uses 1fan, pwm controlled by ecu/bcm taking and giving signals from10’different sources
-I’m using hptuner which has a fan controller section

Fabricator replaces oem fan/radiator/shroud set up with one from cbr using non brushless fans. He was going to insert a piggyback temp sensor and tap into the ac pump wiring and find a switched hot. I feared this was going to cause a wiring nightmare but also a programming mess as even the interior hvac uses radiator fan resistance figures to adjust the temp in the truck and also the fueling graphs. It’s a mess but I fear taping into things, or having the factory harness not running the fans and not causing resistance that is used to calibrate the water temp for the fuel issues...
I hate the genv os.

OK... so to run spal fans, it is my understanding that I need to get the brushless fans, a Y splitter to run from the single oem harness to the two fans where they will run in tandem and not staged. And then find out from spal/cbr if they are 0-5v or 5-0v and then update the tune in the truck via hptuner accordingly?

anything I am missing?


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spal brushless fans run off 3 wires, 12v+, GND and a pwm signal at 128HZ. never program the dutycycle to be at more than 90% or the fans overheat and shutdown.


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Hmmm. Ok. I really hope I have the intel right on the GM factory Pwm signal

jon coleman

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run stock Plus totally seperate additional fan/ thermostat/ power source/ relay direct from battery?


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No, replace stock radiator and stock fan...
now there is a cbr radiator and shroud. It was built with non brushless fans Which won’t operate on the pwm factory system. So he was going to run all the piggy back stuff.

I believe the corvette and camaro folks are running brushless spals on their aftermarket set ups and it took reversing the tune in hptuner to make it work.

but wanted to double check here to see if anyone has messed with the genv stuff and if there were any details I’m missing


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I’m going to temporarily run the non brushless dual 14 inch fans using my spod to manually turn them on and off until cbr sends the new fan and shroud.

each spod channel on the bantam is for 30 amps or less.
I’m assuming to run only one fan per channel, and so run two channels for the two fans.
I’ll turn on One fan when the water temp hits 194 (that’s the first stage on the oem tune I believe) and then I’ll turn the second fan if it hits 215 (which is the middle stage on the tune)

I was originally going to run both on one “channel” or “terminal”, but I think the spal fans draw too many amps..


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The spal fan harness and the oem harness have the +/- opposite. So swapped those.
Left the yellow wire on the spal fan empty.
had to test and determine what the off % was for the spal fan and it turned out to be 87%. It’s kind of hard to find maximum but when the oem tune showed 14% the fans were on so for safety I bumped it to 18% (spal said don’t run over 92% fan speed)... after more research I may change it from 18 to 24...

anyways, after all that, it’s working. So now I just need to swap the new shroud and fan in...