Vintage air Binary Switch / GM Pressure Sensor

[jasonz28camaro]

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?

[badazz81z28]

I don’t see the Benefit. The binary kills the compressor and the trinary works to control the fans. I see no need to introduce the ECM into the equation. You don’t gain anything...

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?

[jasonz28camaro]

My ECM will operate my pwm fan. I did not mention trinary. I currently have a trinary but it will not be used. The benefit would be to eliminate the binary/trinary switch all together and let the ECM control the compressors kill if it can do so. If the ECM cannot kill the compressor based off the GM pressure gauge then I will run both the binary switch and the GM pressure switch.

[dontlifttoshift]

I think you will need both. Compressor control in the factory ECM is more complicated than signal in and out and relies on the BCM and it all talks in CAN.

For future reference, with the Holley ECUs I run only the GM pressure sensor and set up parameters for the compressor so that it can only run with in a certain pressure range.

[jasonz28camaro]

Thanks for the info.

I spoke to someone and they broke it down and said i will require both. Kind of what i thought, just did not know if the gen v ECU did things different.

[badazz81z28]

My ECM will operate my pwm fan. I did not mention trinary. I currently have a trinary but it will not be used. The benefit would be to eliminate the binary/trinary switch all together and let the ECM control the compressors kill if it can do so. If the ECM cannot kill the compressor based off the GM pressure gauge then I will run both the binary switch and the GM pressure switch.

But why? The ECM can control the fans and the trinary can also be wired in to activate the fans when pressures are high. The compressor kill is just a ground. This is how I run mine. I didn’t see any use for the ECM to be involved. The only value would be to adjust engine RPM when AC was going on, but couldnt figure out how to do that.

[jasonz28camaro]

Not sure what motor you are running but mine is a gen V LT motor and I'm using a brushless pwm fan that is controlled via the ECM, it does not have an external PWM controller. This fan needs the ECM to control it and cannot be controlled correctly by a trinary switch, you cannot send a signal to my fan and just turn it on to my knowledge. The ECM also needs the pressure sensor to operate the fan correctly too. The ECM and pressure sensor talk to each other along with coolant temp to determine when to turn the fan on and at what speed then bumps up the idle when if needed when the compressor is on. The other reason is because my engine harness builder recommended running the PWM fan rather than my conventional ones

If I did not run a PWM fan I'd set it up with the trinary like it was before.

[terrydmorgan]

I’m setting up a similar system. My main reason for running the fan with the ECM is to have variable speed fan(s), which can be much quieter, especially while stopped. I have retained the binary switch in my system to turn off the compressor in the event of too high pressure (such as during overheating) and during too low pressure (such as when Freon has leaked out). That is, my ECM controls the fans, but not the compressor, and the binary switch controls the compressor, but not the fans. So I require both the ECM and the binary switch. Theoretically, if your ECM is also controlling the compressor, then the binary switch is redundant. But if the pressure sensor or the ECM fails, the ECM would not shut off the AC compressor, possibly destroying the compressor or the engine. The binary switch is a very inexpensive insurance policy. I’m not an expert, so there may be additional reasons for retaining the binary switch. Please keep us informed on what you discover.

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?

[showdog75]

Imo I'd go with what Bill from BP Automotive told you on ls1tech. He knows his stuff.

[jasonz28camaro]

That’s the plan!

[terrydmorgan]

here's a posting from back in 2015 that might be interesting to you. https://www.pro-touring.com/threads/...fan-controller

[jasonz28camaro]

Thats what I'll be doing minus the programming, good read. Only difference (if it is a difference) is mine is a Gen V setup using a C7 fan. I think the difference is the Gen V ECM sends out a pwm signal right to the fan and the previuos LS ECMs send out a regular signal that goes to a PWM controller that converts the signal to make the fan PWM.

[jasonz28camaro]

Not sure if this is the right way, wrong way or just a different way to do things but this is how my engine harness builder sets up his AC system.

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.

[dontlifttoshift]

So he is supplying a pressure switch to put in the AC system so the ECM knows what the pressure is?

I'm skeptical but curious, who is the harness builder? Got a link?

[terrydmorgan]

Which ECM are you using? E38? I have the E67, and I've been told that the E67 does not support tap shift.

[jasonz28camaro]

So he is supplying a pressure switch to put in the AC system so the ECM knows what the pressure is?

I'm skeptical but curious, who is the harness builder? Got a link?

Heres a link to the pressure switch, this is how a stock gen V operates and probably other LS stuff. Like I mentioned above, the pressure switch, coolant temp, fans, idle and ecm all work together somehow with witchcraft.

Swaptime is building my harness. Mitch was building all the Motech jeep swap harnesses before he started doing his own thing. since he is a ways away from me the harness will be assembled and the ecm flashed and tuned a bit kind of like a mail order tune. Everything should work and I might get it dialed in locally.

[jasonz28camaro]

Which ECM are you using? E38? I have the E67, and I've been told that the E67 does not support tap shift.

E92 I believe. Its from a 2018 escalade 6.2.

The ECM you use is LS based and I'm not sure if its compatible. Maybe the Muscle Car Module I'm using can be used on yours?

[C10clubLA]

I’m a firm believer in sharing what I know with other. It took me 5 months to figure this out, but here is how you get the A/C transducer to work on a Gen 4 swap.

Trucks and vans OS use the ac control panel along with the BCM to send a signal to the canbus to tell the ecm when the compressor is running and when to monitor the ac transducer to provide info to the fans and when to turn on and off with the ac.

Camaro’s don’t use the canbus. They use a 5v reference from the ECM to the transducer and then that send the voltage & pressure back to the ECM and you control the fan state by ac pressure. This keeps your from blowing the relief valve on the compressor.

We had to find a compatible camaro OS that worked on my e38 and was compatible with my TCM.
Works just like the factory system now.
Shot me a message if you need some help.

[robbbc]

I’m a firm believer in sharing what I know with other. It took me 5 months to figure this out, but here is how you get the A/C transducer to work on a Gen 4 swap.

Trucks and vans OS use the ac control panel along with the BCM to send a signal to the canbus to tell the ecm when the compressor is running and when to monitor the ac transducer to provide info to the fans and when to turn on and off with the ac.

Camaro’s don’t use the canbus. They use a 5v reference from the ECM to the transducer and then that send the voltage & pressure back to the ECM and you control the fan state by ac pressure. This keeps your from blowing the relief valve on the compressor.

We had to find a compatible camaro OS that worked on my e38 and was compatible with my TCM.
Works just like the factory system now.
Shot me a message if you need some help.

Hi. I swapped an ls7 converted to wet sump into my 68 camaro. The ls7 is modeled after the 2015 z28. However, i have an e38 controller. (not sure if that matters). Are you saying that you can tune the AC Compressor table so that the engine doesnt bog down when the compressor kicks on? If so, id like hear more on making this work with my setup.