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Discussion Starter #1
Has anyone retrofit the variable a/c compressor with a clutch style compressor? I’m done messing around with my variable on my 2009.5 GT . Please pm text it e mail me with any info. 305-951-2715. Thank you. Alex
 

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The only person I know of that has even tried is Ryan Kerr, Not sure if he is on here but he never got it to work, the BCM got real pissy every time he engaged the compressor clutch
 

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It can be done, but not with the original compressor wiring,as the bcm pulse widths the compressor voltage,you will need a straight 12v source to the compressor and retrofit a low pressure switch in the low side pipe so you don't freeze the evaporator
 

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Bench racing here with probably not enough knowlege.

Could a person rig up something with an arduino based module that could be programed to trigger a 12 relay above a certain pulse width?

Add a clutch controlled variable displacement compressor, like 08ish corvette.

In theory, when the bcm commanded low displacment, the compressor would turn off.

Now, a question, what is the issue with our non clutched AC that would drive one to do this?
Too many rpm in modded cars?
Gerry
 

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Discussion Starter #5
Thank you all for your input . Does anyone know were the bcm is located. I’m not getting any reference voltage. To the compressor
 

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Also the HVAC module controls comp. not the bcm
 

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Bench racing ? LOL, I do this for a living with GM, The Corvettes are not variable as far as knowledge goes,It does the clutch on off via press feedback as most, but the G8 comp. is pulse width for variable control. its shaft is always spinning,yes it can be swapped over and no i would leave it as designed as it is very efficient,Yes there is a wide misunderstanding even for some so called professionals for this system.Always get a new GM comp to avoid the problems so stated and you will be fine

1- I said bench racing as I have never done what I was talking about , suggesting emulating the BCM commands with an Arduino

2 - Not, VD ? , might want to check that. Granted they are not PWM controlled, they adjust their displacement based on pressure differentials. I have one in my LS7 powered engine swap Caprice.
Although it has a clutch, if commanded on, it says on, never cycles.

3 - What exactly do you do for a living at GM ? Anything with code writing in E67 ECU's

Thanks
 

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#1 that is not variable, #2 any one can create write code,try and diagnose all this stuff without throwing parts at it is all im saying,or go ahead and replace the whole dam system
 

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Thank you all for your input . Does anyone know were the bcm is located. I’m not getting any reference voltage. To the compressor
A Tech II will most likely show you what you need.

The aftermarket ones (VXDIAG VCXNANO) are cheap on Amazon and work very well. It's worth the investment in my opinion considering the fact that the dealership charges one (1) hour of labor at a minimum for anything Tech II related.

https://www.amazon.com/gp/product/B0743BFLXB/
 

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Thank you all for your input . Does anyone know were the bcm is located. I’m not getting any reference voltage. To the compressor
The dark blue wire is the 12 v ref from the hvac module,but if you left it unhooked it will shut the system down and you wont see anything,either remove hvac fuse to reset or remove batt cable to reset,seriously your best bet is hook a tech 2 up and go into body> hvac. for a/c codes after clearing them as a simple outside ambient sensor will cause it not to work comp.
 

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1- I said bench racing as I have never done what I was talking about , suggesting emulating the BCM commands with an Arduino

2 - Not, VD ? , might want to check that. Granted they are not PWM controlled, they adjust their displacement based on pressure differentials. I have one in my LS7 powered engine swap Caprice.
Although it has a clutch, if commanded on, it says on, never cycles.

3 - What exactly do you do for a living at GM ? Anything with code writing in E67 ECU's

Thanks
I was the lucky bastard they sent to repair the unfixable electrical demons !
 

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Discussion Starter #12
Ok. The compressor will work but only after I run the car down the street at a spirited run . Then it works ok till you shut off car. Then do the same again to get it to run. 😳
 

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Ok. The compressor will work but only after I run the car down the street at a spirited run . Then it works ok till you shut off car. Then do the same again to get it to run. 😳
That's because the hvac module sees something out of normal and shuts the system down,If you can get a scanner that reads body fault codes, you will most likely get a code in the Body>Hvac module to greatly help in diagnosing it,matbe buy a technician at a dealership a six pack to scan it with a tech 2
 
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jetmech09
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