C1500 0411 e-fans + AC problem

[AlanDC]

I ended up swapping my black box to a 0411 in my 1998 L31 truck. everything is working perfect and now I'm trying to get my Efans to work properly too. I'm using 2 fans with a stand alone harness with 2 separate relays. I was able to turn the fans (1 and 2) ON/OFF with the scanner\special functions.

For those who have done the 0411 conversion and are also running Efans with the AC, have you been able to run the fans with the AC pressures? I want that feature, but because I'm not the first owner of this truck, somebody took the low pressure switch out of the AC compressor body and bypassed that switch signal (short circuit the 2 wires). Do you know if that's the signal the PCM uses to cycle the fans with the AC ON? I can get a low pressure switch and plug it to make it work. I believe it will drain all of the AC gas out of the system but will do if necessary.

I've added some pics of my current OS, AC config (2 fans selected), Fans tab and scanner channels. It's always showing 0.00v on the AC pressure sensor even if I put the AC ON.

Thanks in advance

[AlanDC]

Anyone have been able to get that AC pressure reading in a 1998 Vortec truck?

[Jon S.]

To do what you are asking, you need to physically add a GM A/C Pressure Sensor (to the high side), and connector the 3-wire plug to the PCM.

If your 2002 OS12212156 is from a Truck, you will also need to swap in a Camaro system segment - to allow the A/C Pressure Sensor to function.

You cannot log A/C Pressure - when you do not have a sensor reporting said A/C Pressure.

[AlanDC]

To do what you are asking, you need to physically add a GM A/C Pressure Sensor (to the high side), and connector the 3-wire plug to the PCM.

If your 2002 OS12212156 is from a Truck, you will also need to swap in a Camaro system segment - to allow the A/C Pressure Sensor to function.

You cannot log A/C Pressure - when you do not have a sensor reporting said A/C Pressure.

Thanks a lot for your input. That's what I thought. Looks like I'll have to run a 3rd relay linked to the AC compressor clutch.