adding fan control through ECU Gen 3 5.3's
 

I'm starting to look for a good donor vehicle for my LS swap. I suspect I will end up with a Tahoe or Suburban and it will most likely be a 5.3. I want electric cooling fans and not all of the Gen 3 trucks had this. I don't even know when it started. I just know my 01 Sierra didn't have it and my 06 Tahoe does. If I end up with a water pump driven fan donor vehicle, can I easily wire in factory fans and reflash the ECU to control them? If not, any one know what year the electric fans started or have an alternative suggestion for having electrical fans? I would really like to stay with factory GM fans. They work great, are easy to find, and inexpensive.

Thanks

I would try to use a newer brushless fan to get continuously variable speed. Carl at Vaporworx has a standalone PWM controller for brushless fans. Give him a call.

Don

That's why I was wanting to use the GM fans. I thought they were PWM controlled fans. Are they not?

I'll reach out to Carl, too. Thanks, Don.

The earlier fans are brushed fans and don’t use PWM control afaik. 4th Gen Camaro fans for example just use simple series/parallel relay control for two step hi/lo control.

find your fans, turn them on in the ECU via hptuners or whatever you have and youre good to go.
i too like using factory fans

Thanks, guys. It's crazy to me. I was doing LS swaps 15 years ago. I did my LT1 swap into my TA in 2009. There's so much I have forgotten. I appreciate the help.

I’m not familiar with truck fan setups but if it were a car based LS donor, the fan control is there on the e38 and e67 to allow you to run an OEM PWM fan. The other option is to run a dual fan with one full on at a certain temp and the 2nd at a higher temp.

There are many options for an OEM fan. I believe people use a Volt fan, late Camaro, Corvette, etc. I’m sure a PWM truck fan would be fine provided it fits behind your radiator.

I have a spare Chevy SS fan assembly that’s a nice size. That’s another option.

As long as your ECU has the option and I believe all gen IVs do, you’ll be fine. I think the exception is the connect and cruise e67.

As said above, you can use HPTuners to turn the fan controls on in the ECM. This is an 05 Yukon (green/blue) ecm and 2002 Camaro fans wired up like a stock camaro, low is series, high is parallel. On low you can't hear the fans with the car running. Not sure what you're working on but the 02 fan shroud fit my chevelle radiator like it was made for it, just had to notch the top of the shroud for the upper hose outlet.

Wiring diagram I used, https://lt1swap.com/2004vortec_pcm.htm
Blue 41 for fan 1
Green 33 for fan 2, both are ground triggers for the relay

https://drive.google.com/file/d/13WU...usp=drive_link

Wiring diagram for this setup: https://ls1tech.com/forums/attachmen...pstnnu56hu.gif