Its a computer swap! The stock black box PCM that was found in 1996 to 2000 GMT400 trucks has a few shortcomings if you are using your truck in a high performance application, or you just want to be able to make tuning adjustments to the ECM. by swapping to an 0411 ECM from a later model GM truck, you open up a lot of doors for tuning the engine, having a tow/haul mode, high and low octane spark tables, higher RPM limit, and a whole lot more. Look up and message LEXTECH on the truck forums for the spreadsheet... (didnt want to publicly list his email address) Don't forget to like and subscribe to the channel, and for more behind the scenes content and pictures of projects, you can Follow us on FaceBook https://www.facebook.com/LTtolman For business inquiries, email tolmanperformance@gmail.com Amazon Associates links for parts and gear I use to make these videos... Turbo Blanket https://amzn.to/3aXOAr2 UglyTruck Catch Can https://amzn.to/3jUZ9PX New 0411 connectors with red/blue cover and 100 pins https://amzn.to/3d49SGb Heat Shrink Tube https://amzn.to/3aOKEZu Soldering Gun https://amzn.to/3aTxVoB Main Vlogging Camera I use every day, Sony ZV1. Has excellent image quality and is easy to use for a non-camera person https://amzn.to/3oeFGvi Extra Batteries and Charger for Sony ZV1 https://amzn.to/37zI21X Tripod (gotta have two) https://amzn.to/3dOK52V LED Light on top of camera, eliminates "raccoon eyes" from shadows https://amzn.to/2HpsDX0 Wired Lav Mic for great audio https://amzn.to/3bFJdPr External Shotgun Mic for outside shots https://amzn.to/2Th8h4Q GoPro Hero 7 Black for B-roll and POV https://amzn.to/37sXhJP Chapters 0:00 UglyTruck Update 3:41 What is an 0411 Swap 9:09 How to Pin the Connectors 13:45 Harness Disassembly 17:47 Re-Pinning the Harness 21:52 Helpful Tips 27:42 Its Done