I am using v2 efi live. Thanks for the help! I hope it works.

 

Bummer man. Thats no good

 

It cooled down and I confirmed it does work. I also posted a 2002 operating system in the old format so any one can read it.

If I did it as a .CTZ you have need the latest build from March 1 2015 to read it as that is what I am using currently.

 

Im glad it worked out! Thanks for the help. Ill try to work on it soon and ill let you know.

 

Must be my issue as well, I purchased a 3 relay harness - installed per instructions... fans on all the time. (My tuner tuned my truck for efans knowing I was going to install them at a later date)

Their harness came with a coupon for a "free fan patch." Not having tuning capabilities, I next day aired my PCM to them. Hope it comes back tomorrow without any new issues or quirks.

 

I was wondering if there is an easy way to swap my tune into the stock 2002 tune or do I have to do it all one setting at a time?

 

Sorry for not replying as promptly as I had wished.


Based on the response from the OP I believe the harness is not the right harness. There is a 99 to 02 harness and a 2003+ harness according to a vendor that I contacted.

The 99 to 02 harness should only have 1 pcm pin and a AC tap. It sounds like the OP had two pins tapped.

As suggested earlier, you can reflash to a later OS with efilive. That would allow you to use the late model harness with both pcm pins. Trucks didn't come with Efans till what year? 2006? I am not sure. But my 2004 OS supported the 2 pin harness. Since the vendor in question makes a 2003+ harness I would think you might need a 2003+ OS but maybe the 2002 OS will work. You will have to try it and find out.



I have a 2004 Yukon and did the efans mod. Used the 03+ harness and aftermarket fans. Been having great results so far. One thing to note is that the fans should run two fans low all the time with the AC on. Also, OEM style fans are actually cheaper than many aftermarket products out on the market with 5000+ cfm ratings designed for the size of the factory radiators.

 

What Engine do you have?

Any Mods that your Engine was tuned for?

 

5.3 with head work, cam, ported throttle body and intake. I just wasnt sure if i could copy my tune over the 02 OS or just go through and change everything.

 

There are different harness because the signal is different between 99-02 and 03 up.

Back in the day it was only 1 pin and a trigger because HPT did not have the tables at the time. Now they do. Infact they have a few more tables than EFI for fan settings.

Now you can use 2 pins to the ECM on the 99-02 to run the Efans. But you need to use a 2002 operating system.