The alpha harness is not plug and play as you might assume, even if you do get yours hands on an alpha harness, it will still require the same amount of modification as your LS2 harness. I had the same thought train as you , I purchased an LH8 / 08 alpha harness / 08 Alpha ECU / 08 alpha 4l60e - all sources from different junk yards and I paid a pretty thru the nose for it. My Hummer is a late 07 i5 truck, and after looking at everything , even the alpha harness requires modification. I sent my harness to Jamie (04colyzq8) on 355nation , my understanding is he will get it to as close to plug and play as possible but there is still additional stuff that needs to be done - specifically cutting off the body harness from my 07 hummer h3 and replacing it with an e67 body harness connector.
What you should actually be looking for - if you don't already have it is ....
A. figure out if you LS2 is 24x or 58x reluctor.
A1. if its 24x - you need to start searching for a harness and ecu out of something that is factory 58x...
A2. if its 58x your good to go , and can have your guys doing the wiring harness modification ...
A3. reason why is because all your gauges are setup to work with a 58x style ECU.
B. No matter what combo of engine / transmission / ECU / Harness, you will need to figure out how to adapt your body harness into the ECU.
B1. Which requires you to cut off your current body harness and solder on a new Connector, which will plug directly into the 3rd open port on the ECU...
pictures are worth more than words , Do not pay attention to the other pictures in the H3 swap pictures folder on photobucket , 04colyzq8 already told me I labeled the pinouts wrong , Ill adjust then later as soon as I have all the pieces of the puzzle sitting in front of me again...
