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Discussion Starter · #1 ·
Hello, I have a 2007 G6 sedan.
I have been doing a lot of research lately trying to figure out how to figure out how to get the turn signals and brake lights on separate circuits. If you want to go the route that will probably work, you could remove the bulbs from the left and right, tap into the high top center mount brake light, use that as your brake light signal, and tap into the front right/left turn signal bulbs for your turn signals. That (I think) would work exactly as I want it to without having any hyper-flashing, I will show you how to do that as well).

But for those of you (like me) who want to go the complex route of actually reprogramming things, and doing it the "OEM" way; I have a solution to it. However I don't know how to execute my solution. It's a bit complex, and might not be possible, but for those of you who want rear amber turn signals (which have been proven to be far more effective as turn signals, than having the brake lights act as turn signals) here's what I've found so far:

Okay, so to begin with, the Pontiac G6, and Saturn Aura use the same BCM, same outputs, and same inputs, with slight variations, but those variations are unrelated to what I'm talking about. On the G6, Pin A9 on connector C3 (or J3, they're the same thing, just different name, depends on what BCM you have) on the Body Control Module (center console in the passengers side foot well) is the output of the Right Rear stop/turn signal lamp. And pin A12 on the same connector is the output of the Left rear stop/turn signal lamp.

On the Saturn Aura, the same exact pins (A9, and A12) are used as the rear turn signals. The Saturn Aura has separate turn signals and brake lights. So when you put your turn signal while you apply the brakes, a different bulb will start flashing and all 3 brake lights will stay on. This is what my goal is (from a wiring perspective, I'll worry about where to actually put the turn signal bulb later, maybe I'll design a custom housing for it, but that's for later). For the brake lights on the Saturn Aura, the third brake light signal is split and used for the brake lights.

TLDR; Same G6 and Aura rear turn signals have the same output on the BCM, the only difference is that the G6's turn signals act as brake lights in addition to turn signals. So I need help to find out if it's possible to get my BCM to have the rear turn signals act as only turn signals (like on the Saturn Aura). I looked into getting a BCM for a Saturn Aura and putting it in my G6, but I don't think that's possible due to how programming a BCM works. You program a BCM using the VIN and all the RPO codes (I think) and once it's programmed you can't reprogram it. Is there any way I can use a Tech2 function to program it? Or any possible way to make my rear turn signals to not act as brake light?

If you read this far and want to know how to do this without going through all that, simply do this (this is in theory, I have not tested it):

Cut the wires going into pins A9 and A12 of the C3 (or J3) connector on the BCM, but not too far. Connect those wires coming out of the BCM to load resistors and connect the load resistors to ground. For the remaining wires that go to the rear bulbs, connect the wire that did go to pin A9 and tap it into the wire coming out of Pin 38 on connector C1 (although that wire goes to the under hood fuse block next to the battery, so I don't know if that wire is designed to power a light bulb). And connect the wire from A12 to Pin 56 on Connector C1. Not sure if that will work, and I won't be cutting any wires until I figure out if any of this will work. I'd love to know if anyone has any way of figuring out if this would theoretically work without risking a car's electrical system.

I really hope someone can help me know if any of this is possible or how we could theoretically make this work without braking the bank.

I'm also working on installing cruise control on my car (it has an aftermarket cruise control, and I have cruise control buttons, and I want to see if it's possible to use my buttons instead of this aftermarket thing. I'll post something about that if people are curious enough. BTW, the cruise control doesn't need any reprogramming. According to my research (and the Rostra installation manual, for the 250-1775) G6's have cruise control, it's just not wired up (I think).
 

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Discussion Starter · #2 · (Edited)
Hello, I have a 2007 G6 sedan.
I have been doing a lot of research lately trying to figure out how to figure out how to get the turn signals and brake lights on separate circuits. If you want to go the route that will probably work, you could remove the bulbs from the left and right, tap into the high top center mount brake light, use that as your brake light signal, and tap into the front right/left turn signal bulbs for your turn signals. That (I think) would work exactly as I want it to without having any hyper-flashing, I will show you how to do that as well).

But for those of you (like me) who want to go the complex route of actually reprogramming things, and doing it the "OEM" way; I have a solution to it. However I don't know how to execute my solution. It's a bit complex, and might not be possible, but for those of you who want rear amber turn signals (which have been proven to be far more effective as turn signals, than having the brake lights act as turn signals) here's what I've found so far:

Okay, so to begin with, the Pontiac G6, and Saturn Aura use the same BCM, same outputs, and same inputs, with slight variations, but those variations are unrelated to what I'm talking about. On the G6, Pin A9 on connector C3 (or J3, they're the same thing, just different name, depends on what BCM you have) on the Body Control Module (center console in the passengers side foot well) is the output of the Right Rear stop/turn signal lamp. And pin A12 on the same connector is the output of the Left rear stop/turn signal lamp.

On the Saturn Aura, the same exact pins (A9, and A12) are used as the rear turn signals. The Saturn Aura has separate turn signals and brake lights. So when you put your turn signal while you apply the brakes, a different bulb will start flashing and all 3 brake lights will stay on. This is what my goal is (from a wiring perspective, I'll worry about where to actually put the turn signal bulb later, maybe I'll design a custom housing for it, but that's for later). For the brake lights on the Saturn Aura, the third brake light signal is split and used for the brake lights.

TLDR; Same G6 and Aura rear turn signals have the same output on the BCM, the only difference is that the G6's turn signals act as brake lights in addition to turn signals. So I need help to find out if it's possible to get my BCM to have the rear turn signals act as only turn signals (like on the Saturn Aura). I looked into getting a BCM for a Saturn Aura and putting it in my G6, but I don't think that's possible due to how programming a BCM works. You program a BCM using the VIN and all the RPO codes (I think) and once it's programmed you can't reprogram it. Is there any way I can use a Tech2 function to program it? Or any possible way to make my rear turn signals to not act as brake light?

If you read this far and want to know how to do this without going through all that, simply do this (this is in theory, I have not tested it):

Cut the wires going into pins A9 and A12 of the C3 (or J3) connector on the BCM, but not too far. Connect those wires coming out of the BCM to load resistors and connect the load resistors to ground. For the remaining wires that go to the rear bulbs, connect the wire that did go to pin A9 and tap it into the wire coming out of Pin 38 on connector C1 (although that wire goes to the under hood fuse block next to the battery, so I don't know if that wire is designed to power a light bulb). And connect the wire from A12 to Pin 56 on Connector C1. Not sure if that will work, and I won't be cutting any wires until I figure out if any of this will work. I'd love to know if anyone has any way of figuring out if this would theoretically work without risking a car's electrical system.

I really hope someone can help me know if any of this is possible or how we could theoretically make this work without braking the bank.

I'm also working on installing cruise control on my car (it has an aftermarket cruise control, and I have cruise control buttons, and I want to see if it's possible to use my buttons instead of this aftermarket thing. I'll post something about that if people are curious enough. BTW, the cruise control doesn't need any reprogramming. According to my research (and the Rostra installation manual, for the 250-1775) G6's have cruise control, it's just not wired up (I think).
Update, I have found some evidence that proves it's probably possible to complete this via a Tech2 reprogramming (Still not 100%). Because some people like exporting their Corvette's across the pond to Europe, they need to comply with European lighting requirement. It just so happens that the C6 Corvette has the same BCM as the one from the G6/Aura/Malibu!! I haven't found the exact way in order to actually complete this reprogram, but I've read a couple of forum threads on the topic, and most were talking about replacing wiring harnesses (which the more I think about, might be easier to do if you don't plan on running custom wiring. You could probably buy a tail light harness from an Aura, and use that if you don't want to run any custom wiring, don't take my word for it). I'm gonna call around and see if there's any shops out there willing to help me, and take a peak at the tech2 software to see if it will work or not.
 
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