Does anybody know if I can eliminate the binary switch my Vintage Air system came with if I intend to use the GM ac pressure sensor to run the motor correctly and control the fans for my LT swap? The real question would be does the GM pressure sensor on the Gen V ECM act as a safety device like the vintage air binary switch and cut off the compressor? Do I need both or can I just run the GM sensor?

 

The GM pressure sensor is for idle tables and to control your fans when the A/C is on. You will still need the binary switch to protect your compressor from high and low pressure.

We we have a crimp in fitting that makes integrating the pressure sensor a breeze.

Hope this helps!

 

That’s funny. I came across your crimp sensor and emailed you last night.

Vintage air suggested I use one of those crimp splices with the pressure gauge on the #6 line and i saw you only carry the #8 size crimp splice. I’m not too familiar with the lines coming and going on the VA system at this point but if the #8 crimp will work let me know where to put it please.

Im a repeat customer btw. You built me a harness a while back. It worked perfect!

 

I replied to your email, I’m gonna reply here too just in case anyone else is curious. Our sensor will work with all GM controllers. The sensors all have the same threads and the readings do vary minimally, but it in a stand alone environment those minute differences are moot.

We do have some #6 crimp in fittings. We had to have them custom made.

Most generally Vintage Air customers will use #8 fittings on the high side line between the compressor and the condenser. That line is most generally #8!

I would recommend calling Vintage Air just to make sure you do in fact have a #8 line in that section of your system.

 

I spoke to VA and they told me they recommended #6 only because there is more hose and available space to choose where to add the splice. They said I could use the #8 splice but I may be limited in selecting a location to install the splice. I'll be ordering the splice and sensor from BP Automotive, thanks for the help.

On another note, on my particular setup my engine harness is being reworked and another module (aka Muscle Car Module) is being added to control a few things like reverse lights, tap shift and neutral safety switch. This module also has a 12v input where the ac compressor power wire ties in at rather than going to the binary switch then to the compressor, its being taken over and the ECM will now control the compressors on and off based on pressure. This is what the harness builder said when I asked him about the binary switch. "my fuse panel will control the compressor off a relay. Basically the muscle car module takes on the command and transmits a can bus message to the ac compressor. The computer then checks the pressure and then sends a signal to the relay to allow the compressor to turn on just like factory. If the pressure is too high or too low it will not let the compressor function." His words might be a little mixed up but it sounds like the module sends a signal to the ECM and it checks the pressure then activates a relay that turns on the compressor and the harness has the power wire built in that runs to the compressor. If this is accurate I will not require a binary switch. Not sure if the LS EMCs work like this or if its just a Gen V thing? I'm going to give it a shot though and see how it performs, wont know for a few months but my faith is in the harness builder.

 

Jason can you give more information about this Muscle Car Module, who is re-working your harness etc. I have the same engine with Vintage Air, Spal PWM fan and I understand that the ECM can control the compressor etc. Any info would be greatly appreciated, thanks

 

https://www.swaptimeusa.com/

his name is Mitch.

 

Hey guys, I know this is a little old but I was hoping for help. I got the module from Mitch but I haven't heard back yet and want to do this today. I didn't get the Canbus plug because I have Dakota gauges plugged in there so it's just a bunch of wires I need to connect.

My biggest question is the AC hook-up. I have a Restomod air unit and I'm not really understanding where this brown AC wire would go. Great that I don't need the pressure switch but I'm stuck. I'll attach the wiring diagram and etransfer beer for the answer haha.

The only other two I haven't figured out is the CAN High (blue) and CAN Low (white), probably have to splice them into my OBD port???

Thanks in advance,
Sean

 

I'm not sure if this is correct, sorry I couldn't attach it to the pm.

Sean

 

No, the compressor gets power from the ECM. Resto mod +12v converted to ground to module is all you need to do, the rest is already present in the engine harness. The module talks to the ECM and if you got the factory wiring it’s wired to the compressor via the engine harness. The low pressure switch is also tied into the engine harness.

 

Thanks Jason, I got ahold of Mitch and went through it with him. It didn't make any sense to me because I was missing a bunch of wires from the ECM as well as the sensor you mentioned above that I need to order. So this is what we came up with in case anyone else goes through this.

Pinouts needed blue X1:
32-AC compressor relay control
6-AC pressure sensor signal
21-AC pressure sensor 5v reference
22-AC pressure sensor low reference

Pin 32 goes to post 85 on relay, 12v ignition to post 86, power to 30, and post 87 goes to the compressor.
Module is converted to ground via relay like you said.

Sensor wiring to go still, feel free to correct me if I'm wrong again haha.

Sean