A/C tuning with Vintage Air.

[beaterku]

Morning All,

Working on finishing up my Vintage Air in stall on my C10. Engine and PCM are from a 2003 Yukon Denali.

Service #12582605
OS #12593058
MVPI 1
VCM 3.6.26 (it's what came with it and I've heard horror stories of bricked units so I left it be as it works)


My plan was to use the high pressure sensor to run the fans based on pressure and let the vintage air control the clutch. My rational was I have 2 fan, a 3-relay setup so I can run both a half speed and both at high speed, let the ecm run the low speed when pressure approaches 250psi, and if it keeps rising, enable the high speed. After reading this thread and that thread, I am starting to thinking this is not going to work as I had anticipated.

Last night, I hooked up the pressure sensor. I created a custom math to covert the PID to a pressure reading and can confirm that the ecm is seeing and reading pressure correctly. What I did to test my theory was hooked the sensor up, use my shop air and a blow gun with a rubber tip to apply pressure to the sensor. It shows in the scanner exactly what my shop air indicates. So in my tune, I changed the enable and disable pressures to 35/30 and 50/45 respectively to see if I applied pressure to sensor if it would turn the fans on. It did not. The truck was not running and VA was not on as I am still mid install. I had the ignition to run. Fan settings are based upon a 2001 F-body tune as a starting point to populate the cells.

First question, does the truck need to be running for this function to work correctly? I wouldn't see why it would, but figured it was worth asking.

Second question, reading both of these threads, it seems as though some P59's have the needed hardware, and some done. I am leaning towards mine doesn't but want to verify I am not missing something here?

Thank you all!

[beaterku]

Ok, I did a little more digging and found this thread over on pcnhacking.net. According to this PDF, my ECM does not have the hardware for the ecm to control the fans in the way that I'd like if I am reading this correctly. It looks like an 04 ecm #12586243 might do the trick, although there is conflicting information on this as well.

Looks like the ecm needs IAC drivers to make the AC work. I am not finding definitive information, but it looks like the ecm needs to see the analog 12v ac request signal to do anything with pressure controlled fans. If I flash my 03 config to a 04 12586243 ecm, it should work? Does this sound correct?

[Roundhouseman]

How have you progressed? I'm curious how you wired your system up. LT1swap.com has good info on AC setups. I had PCM Serv #12586242 HDW #12583660. I just purchased a PCM from a 04 Silverado Serv #12586243. I am going to wire it up like a 04 Express Van and have it control 2 electric fans.

[jnrice305]

Has anyone figured it out? Ive got an 06 silverado Gen III ecm and I can not figure out how to get the ac request to operate. I have looked at and 06 express file and set everything in my ECM to the same settings but still powering pin 17 will not give me the AC request ON. In my case, Im just trying to use the ac request to bump the idle for my rock crawler. Now I have read in some Forums that I would need to download the Express Van file to make it work? TIA

[torque_383]

Hello,
i have the same problem. see my thread here:
https://forum.hptuners.com/showthrea...vy-Van-LS-swap
i'm using basacly the same schematic.
my question is how and were in hp tuners you have to adjust the settings. is there a way to log the pressure sensor that is connected to pin 14?
my tuner tried a bunch of setting to get the fans work when the ac is on.

thanks