Plain English Disclaimer:    Over the years we've presented a ton of information here on this website, in videos, verbally over the phone and in printed instructions and supplements.  We've done our best to test and verify each suggestion made and at the time any information is conveyed it is believed to be accurate.  However GM makes calibration changes to each of their Electronic Modules internal software and hardware systems on an irregular basis.  We will do our best to update the information here on this website in a timely manner once a new challenge is discovered.  Check back often for updates.

Modify any Duramax, Gen 5 L83 L86 or LT1 Engine Wire Harness for use in your swap project.

Sample photo only.  Harness shown is a new build with available options.

Leave it to us

Doing it yourself sometimes doesn’t pan out. The typical Gen 5 LT1 or Duramax harness has hundreds of individual wires and each has a specific place in the harness.  While setting it up for standalone yourself is possible with the right tools and information, you will also need to bring plenty of patience. Rely on our knowledge and experience instead to provide you with a harness that requires just 4 connections to make your Gen V or Duramax Swap Engine run. Take a look at the Gen 5 LT and Duramax tabs for more details and examples of our work.

(Stand Alone Harness, LLC)


  • Every harness is completely cleaned, degreased and power-ground circuits are load tested.

  • The normal turnaround time is 2 weeks.

  • Simple 4 wire hook up to make the engine run. (Ground, 12V Constant, 12V Key On, Fuel Pump)

  • Delphi Fuse Block including Relays for ECM/TCM and Fuel Pump (LT only).
  • 5' OBD diagnostic port is included on every harness.

  • Accelerator Pedal Connections are on every harness.  

  • Contact us for a quote or questions on our harnesses.