I am working on a 2014 camaro with a manual transmission. I would like to install a steering wheel from an automatic and use it to control some auxiliary systems that I am installing such as a line lock. I have looked over this post and there is some interesting information in it but I am not an expert and am struggling to find the solution I am looking for.

https://forum.allaboutcircuits.com/threads/paddle-shifter-add-on-circuit.143000/

In my use case there is nothing using the purple data wire that is used to signal the BCM. I would like this line to signal one relay to close when the right shifter is pressed and signal another when the left is pressed. I have a post on another forum as well where we are discussing the possibilities but I think some more specialized skill sets are required to answer my question and get to a solution. Any help would be greatly appreciated.

Link to my other forum post:
https://www.camaro5.com/forums/showthread.php?t=602389

 

Welcome to AAC.

The first question I have is 'What happens when you tap one of the paddles?' Does it present a resistance change? A voltage divider change? Somehow the BCM reads that signal and determines what the driver wants to do. On my wife's car radio with steering wheel controls, there is a series of resistors. When you push a particular button you change the resistance read by the radio. The control circuit responds in accordance with what engineering determined a particular button will do. So I'm just guessing here, but it might be an analog setup where one voltage is present, say a full 5 volts. When you push one paddle the voltage may drop to 3.3V. When you push the other paddle the voltage may drop to 1.7V. Some sort of comparator determines what signal has been returned and whatever that circuitry is designed to do - it performs that function.

As for your paddle shifters, I have no experience with them so I really can't offer any valid responses. Just what I suspect to be the case.

 

This is supposed to be the internals of a Camaro paddle:

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I wasn't able to find a schematic, but this is a Corvette and I expect it works the same way. If so, the phot above would be the left paddle since it has the resistors in it.

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View attachment 261476
@Yaakov This has been the most detail that I could find on the harness and I have not found a detailed circuit diagram yet. As far as the button pictured above I believe that you are correct. here is the info I got from the camaro5 forum:
" the left switch has 2 resistors...a 4120 ohm and a 1370 ohm. The right switch has a single 634 ohm resistor"

@Tonyr1084 I do not have an automatic and have not done any testing yet but I believe it is just as you describe from what I see in the switches, just starting a discovery on this. I am not sure if I the purple wire even running to the wheel or if there is power to it at all. If I am correct there is just a wire that is not being used but getting voltage from BCM but doing nothing since the pin out on the manual wheel would not be connected. I would like to try and use off the shelf parts as much as possible and it is starting to seem like an arduino used to detect the voltage drop on that line and activate the desired relay.

I am still looking from a better diagram and will provide more info as I dig it up.

 

View attachment 261476
@Yaakov This has been the most detail that I could find on the harness and I have not found a detailed circuit diagram yet. As far as the button pictured above I believe that you are correct. here is the info I got from the camaro5 forum:
" the left switch has 2 resistors...a 4120 ohm and a 1370 ohm. The right switch has a single 634 ohm resistor"

@Tonyr1084 I do not have an automatic and have not done any testing yet but I believe it is just as you describe from what I see in the switches, just starting a discovery on this. I am not sure if I the purple wire even running to the wheel or if there is power to it at all. If I am correct there is just a wire that is not being used but getting voltage from BCM but doing nothing since the pin out on the manual wheel would not be connected. I would like to try and use off the shelf parts as much as possible and it is starting to seem like an arduino used to detect the voltage drop on that line and activate the desired relay.

I am still looking from a better diagram and will provide more info as I dig it up.

I think all you need is a DMM to test the resistance you see between ground and the wire that is coming from the paddles. It should be that one of them has one resistance for pull and another for push, and the other paddle has the reverse results.

 

I know this isn't what you're looking for but my wife's 09 Venza steering wheel radio control button panel is wired something like this: (below) You can see how selecting different buttons bypasses so many other resistance values, changing a controlled voltage. You're going to be looking at something similar in your project.