Vintage air question

[Gunnin4ya]

I have a 5.3 gen iii and I am trying to install it. I want to use the pcm to run the a/c system but it is a stand alone system from vintage air. My gen iii harness says I have a lime green wire that is for the a/c clutch and a red that is a/c request. Where do I hook them up to? I have found that I have a Sanden sd7 compressor and it will have to be tuned to fixed in hptuner. Just really don't want to mess up my new system. Any help would be great. Thanks

[Dustytrix]

If its a stand alone from vintage, well thats all you need.

[87chevy.com]

Originally Posted by Dustytrix

If its a stand alone from vintage, well thats all you need.

I'm sure that's not what he is wanting to know... perhaps he wants to know how to have the vintage air be controlled by the ecu like factory..

I dont jave vintage air, nor a diagram. So post up a diagram and I could look at at and give you advice...

More than likely the a/c request will be the power from the stand alone vintage air unit to compressor..

If the harness was modified like factory and it will have a relay, that output wire (ac clutch wire) will go to the compressor.. so it will then operate like factory

Im sure vintage air has similar instructions

[First c10]

What is the benefit of having the ECM control the A/C? other than shutting it off when you floor it? unless you are using the ECM to control electric fans when the A/C is turned on???

[Gunnin4ya]

Control fans, idle and shut off over whatever rpm you set it to. Sanden sd7 is good to about 6000 rpm. Mine can spin up to around 7400 before the limiter hits.

[First c10]

Originally Posted by Gunnin4ya

Control fans, idle and shut off over whatever rpm you set it to. Sanden sd7 is good to about 6000 rpm. Mine can spin up to around 7400 before the limiter hits.

Idle is a reason all by its self.....

[ls1nova71]

Originally Posted by First c10

Idle is a reason all by its self.....

I think most people underestimate the abilities of the PCM. It is a microprocessor capable of very small changes at very high speeds, so the IAC (Idle Air Control) motor, or throttle body in DBW applications can adjust for just about any load thrown at it. Combine that with the fact that modern compressors don't put that big of a load on the engine, running an A/C system stand alone isn't a bad idea. Sure, you will need a trinary switch to run the fans, and you loose the full throttle cut off, but back in the day, you just turned the air off for a second if you needed to race the guy in the next lane! PCM control isn't as easy on some set ups as it is on others, so some times it just isn't worth the hassle.

[Gunnin4ya]

May be easier to put a wot switch on the pedal? Btw nova, I have everything on the motor hooked up like you suggested. Works great. Took me a little learning what to do with hptuner. But runs amazing

[davepl]

This is TOTALLY from memory from having looked at the instruction sheet a couple of years ago on a friend's truck, so please double-check it. But I'm a visual learner so this should be close:

On the bottom right of the Vintage wiring diagram, you'll find a manual override knob which activates a blue or white wire. That's the one you want to tie your ECM's green wire to. When the green wire goes LOW (ground signal), it will act like the manual override switch and activate the relay just like the switch would if you manually flipped it.

[davepl]

I went out and found the chart I was looking for, I think this is it. I was close! It's the white wite that connects to the knob, and I think the blue is equivalent.

[Gunnin4ya]

I will give it a shot

[ls1nova71]

Gunnin4ya, what year is your PCM? This make a big difference on if its doable.

[Gunnin4ya]

2002

[First c10]

I have a 2008 E38 ECM and want to set it up so the ECM knows the AC is on. Is it X1-pin 63 that needs to be connected? and is it 12+ or (-)?
I can find a schematic for the AC. I am also running an Old Air products Hurricane system.

http://www.lt1swap.com/E38%20ECM%20C...%20Pinouts.htm

[sprint_9]

Originally Posted by First c10

I have a 2008 E38 ECM and want to set it up so the ECM knows the AC is on. Is it X1-pin 63 that needs to be connected? and is it 12+ or (-)?
I can find a schematic for the AC. I am also running an Old Air products Hurricane system.

http://www.lt1swap.com/E38%20ECM%20C...%20Pinouts.htm

The way I understand it is that Pin 63 controls the compressor clutch in a stock application, this pin is controlled by the BCM, since most swaps dont use the BCM that pin is essentially worthless. The pins you should look at would be 12, 13, and 34. These would run to a separate pressure switch specific to the stock LS AC systems. This would sense pressure in the system and run the fan and adjust idle as required.

This is all based on a little reading and how my BP Automotive harness was setup, so take this for what its worth.

On my truck Im using Vintage Air, but the principal is the same. The standalone AC system has its own pressure switch for the compressor clutch. Since the ECM uses different voltages than what the AC clutch requires it also has a pressure switch for the ECM.

Here is a picture of my LS ECM switch, I bought a port and welded to one of my aluminum lines

[First c10]

Great info and pic. Which pin needs to be hooked up to the pressure switch?
what switch do you have?

12 0.35 OG/BK 380 A/C Refrigerant Pressure Sensor Signal (CJ2/C67)
13 0.35 TN 5514 Low Reference (4.8L/5.3L6.0L/6.2L with CJ2/C67) -A/C Refrigerant Pressure Sensor Pin 1
63 0.35 D-GN/WH 459 A/C Compressor Clutch Relay Control (CJ2/C67)


I wired a relay to turn my fans on high when the AC clutch is engaged. but would like the ECM to know the AC is switched on

Originally Posted by sprint_9

The way I understand it is that Pin 63 controls the compressor clutch in a stock application, this pin is controlled by the BCM, since most swaps dont use the BCM that pin is essentially worthless. The pins you should look at would be 12, 13, and 34. These would run to a separate pressure switch specific to the stock LS AC systems. This would sense pressure in the system and run the fan and adjust idle as required.

This is all based on a little reading and how my BP Automotive harness was setup, so take this for what its worth.

On my truck Im using Vintage Air, but the principal is the same. The standalone AC system has its own pressure switch for the compressor clutch. Since the ECM uses different voltages than what the AC clutch requires it also has a pressure switch for the ECM.

Here is a picture of my LS ECM switch, I bought a port and welded to one of my aluminum lines

[First c10]

ok so this is the sensor. I am guessing that the pins 12/13/34 go to it? I pulled a diagram for low V reference on LT1SWAP.COM

http://www.lt1swap.com/pictures/5-Vo...0Reference.gif

https://www.amazon.com/ACDelco-15-51.../dp/B01LWENR28

[sprint_9]

12 0.35 OG/BK 380 A/C Refrigerant Pressure Sensor Signal
13 0.35 TN 5514 Low Reference A/C Refrigerant Pressure Sensor Pin 1
34 0.35 GY/WH 2700 5-Volt Reference 1 - A/C Refrigerant Pressure Sensor Pin 2

I believe that is the right switch, matches mine.

(4063) R134a Aluminum Weld-On Switch Port is the weld on port I used, search on ebay. There are also fittings you can crimp inline on a hose as well.

[First c10]

Thank you for the pictures I am sure I have the plug that was removed from the harness. I will have to add it back in. And remove the relay I added.

[First c10]

Just started to plumb the ac lines and grabbed the GM pressure switch and found out it is m10x1.0 thread pitch. I found an adapter to go from the 1/4” r12 flare (7/16-20)to m10 switch port size.
I am installing a tee one side for the binary switch and the other for the GM pressure switch to ECM.

https://coldhose.com/switches/7-16-f...itch-port.html

[First c10]

Follow up to this thread.

The gen 4 stuff needs a special canbus box to tell the pcm that the ac is on for the pcm to control the fans during the use of AC.
So on to a trinary switch if a relay to turn on the fan when the ac calls for the ac clutch to engage.

[NorCalAnthony]

Sounds like this may have been figured out already but I ran across this fan harness from Painless (#30118) that might be worth sharing/asking about. It's a three relay setup and uses the stock high/low wires coming from the PCM to control when the fans come on but has a wire that splices in to the compressor wire to kick on the fans when the AC clutch is engaged. With the Vintage Air unit being separate/stand alone from engine's harness and computer, wouldn't this be good way to have the fans work like they should without complicating things with the computer? I showed this to the guys making my harness (Speartech) and they said it should work just fine but here's the wiring diagram and a pic of the harness in case anyone wants to take a look and confirm or deny.

[siggyfreud]

Sounds like what you want/need is the ECU to be aware of the AC coming on/off as opposed to controlling it. Having the ECU control the AC is illogical, as you control the temperature. You want the ECU though to respond to the AC being activated. Ideally the ECU would have an input so when the compressor grounds, it knows the AC is on and adjusts idle and kicks on your radiator fans. Essentially, the ECU would be taking the place of the separate temp sensor and trinary switch you might use in a non ECU application. The ECU would then either kick on the fans via temp demanding it, or the AC demanding it.

[orngsikL]

So I’ve got it figured out and working on a Gen 4 swap with an e38.

Trucks and van OS used the ac control panel head to send a signal to the bcm and canbus to tell the ECM when the ac was on. Without this setup, the truck and van OS will not read the ac pressure transducer.

Now on the Camaros, it doesn’t use this setup. All they have is a pin on the J1 connector that is a 5v ref, that goes to the ac pressure transducer and send the info back to the ecm. So you have to use a camaro OS to make it work. Find a compatible camaro OS that is also comparable with your TCM. You will also have to run a camaro accelerator pedal to use the camaro OS.

It works. You then use the ac high side pressures to control when the fans come on. Got mine setup and finished today.
Shoot me a email if you need some help.
Nick
C10clubLA@gmail.com