Guys, I went ahead and ordered the harness so I don't have to mess with making it myself. One last time, will this work on a 99-02 PCM? I saw a few yes's, but I just found two links that say pin 33 is for the air recirculation door on the 99-02's.

Here is one from ls1tech https://ls1tech.com/forums/pcm-diagn...-6-0l-lq4.html

Could it be a different pin on the 99-02's? Even though these trucks never came with the fans, I don't see why one pin would be there, but not the other.

Please, someone figure this out so I don't have to.

 

^^^ me and corey(blackgmc) just hooked efans up on my 00 and we used pin 33. in the tune you just change air recirculation to fan#2 controls.

BTW its the pin 33 on the opposite connector as the pin 42. on my 00 thats blue 42 and red 33

 

yep, it worked after my dumbass accidentely switched 2 wires on the harness and it went up in smoke!! But we rewired it and it worked like a champ!

on your tune you have to go into the AC settings and change what the Pin 33 does. You can choose Fan #2 or AC recirulate

 

was this your attempt to put my truck out of commision so you'd be faster

 

x2

 

great info here fellas!
i just got a set of ls1 fans for the Z71, i need to make me one of them harness when i have time.

 

I'm wondering if the Neson harness will work as is, but take the wire that would normaly go to the green wire for ac compressor and just tap it into pin 33?
Maybe this was asked but I'm not clear.
Now that we see that this will work on the 99-02 trucks, I want to be sure of the config. of the harness.

 

I don't believe the nelson harness will work for pin 33... From what i remember the nelson harness the AC trigger is looking for a voltage, not a ground like the pin 33 needs....

 

So what would need to be modified on the Nelson harness to make it work with pin 33?
Does anyone else make a plug and play harness for the electronicly challenged like me?

 

It appears that EFI Live has the ability to switch air recirculation door control to fan #2 control for pin 33 for 99-02 pcm, sadly I don't see it in HP Tuners even in the new bata
Is this what's need to control fans with pin 33 on the 99-02 pcm?