No cruise CTS-V CTSV stand alone, or my own custom OS E67 58x T56 T-56 impossible

Is there no setup that has cruise working on a non factory application for those of us with a E67, 58x motor and T-56? I've tried everything under the sun! I can not get the 06-07 CTS-v cruise to work, scanner says I'm turning it on with the switch, but it won't activate? I don't see any wiring diagram for the cruise release signal from the brake pedal to the PCM, as it goes through the BCM on the CTSv, I'm thinking that's why it won't work or because they have adaptive cruise and since that modules not there it won't work. All other factory T-56s that I know of with a E67, use the bcm for the cruise, no signal direct from the switch to the PCM?

So the only way we can have cruise is to use a trailblazer or Colorado E67 automatic , and dummy in a T42, but it causes drivability issues even with a clutch switch signalling the TCM into neutral when you depress the clutch. But cruise works

Ok so lets remove the TCM, then... well now we get no speedo, ok using hpt we switch from "auto" to "manual" well now the scanner shoes speedo pegged at 158mph, and we cant start the thing with out hot wiring the starter.... that's fun! And no cruise

Well I navigate the pcms raw code, make a few changes of my own, low and behold the scanner now reads proper speed, reverse lockout works, starting circuit works, cruise works...but cruise only works in 3rd or 4th, usually only in 4th! So that makes sense only gear the two auto and T56 share is 4th as its 1:1. Well I find the gear ratios in the raw code and I correct them, still cruise only works in 3rd or 4th. I skew the speedo slightly and it allows cruise to work in 3rd, 5th, and 6th. That's the best I can do!

So now I must admit defeat, and after months of work, and $$$$ spent I am throwing in the towel, and I ask how do I ever get cruise to work properly?

So do I run a convertor box from 58x to 24x, and redo the harness go back to the tried and tested E40, as cruise worked on it??

Or do I buy a cruise convertor box for around 350.00 that's a universal cruise DBW kit, doubt the cruise light will work on my dash with it

So no one that has a hot rod with E67 has ever gotten a T56 with cruise to work properly without a TCM?? That I know of? Help.....


My trucks a 2004 Colorado with LH6 58x 5.3L MN12 06 GTO T-56. swap. I also have a customer with a 09 Colorado 4.8L 58x magnum T-56 swap. We are both in the same boat, neither of us have cruise...