LML/LGH Custom Standalone Harness/Solution


DmaxSwap.com has worked to develop the cleanest solution for wiring your LML/ LGH Duramax drivetrain for simple operation with nothing more than power, ground, ignition and cranking signals. This purchase will include conversion of your donor engine to chassis harness (see video on our ordering guide), tuning your ECM and test starting the system. If you still have your BCM, please send that as well. Additional selections give you the option to purchase a TCM tune, donor harness, donor ECM, donor TCM.

* We do not offer this harness without ECM tuning as every setup is tested before it gets sent to you and requires our proprietary solutions.

** Dmax Swap LML standalone solution supports 2011-2014 LML/Allison drivtrains as well as 2015-2016 LML/Allison drivetrains.  For 2011-2014 drivetrains you can supply your donor harness and modules for tuning.  2015-2016 drivetrains will require a 2011-2014 ECM and TCM which we can supply so be sure to select “Tune on new module” for the ECM and TCM when ordering a standalone solution for 15/16 LML.

*** Only stock power levels only for LGH/6L90 applications unless transmission is built.

Need a pedal? LML Accelerator Pedal.



Important info about our harnesses…

Lead time on harness conversion is generally 3-4 weeks from the time it is received and checked in. At the time of check-in, the harness will be inspected and subject to additional charges (either mandatory or suggested) if there are any issues with wires, corrosion, pins or connectors.

We do not support Duramax integration into late model vehicles. This includes any integration with any factory gauges, factory body harnesses, etc. It doesn’t mean it can’t be done, just that we don’t support it. You will not retain control of the AC, tow haul or any other factory features that are controlled through the BCM.

Your harness is set up for standalone use only which in basic terms means the engine will run and the transmission will function. Due to the complexity of modern vehicles and their control systems, donor vehicle functions, conveniences or “nice to haves” are not offered or supported in any way as follows:

Tow-Haul Mode, Tap Shift, Electric Transfer Case Shifting, Axle Engagement, Duramax Idle Up, Fled Fuel, Starter Solenoid Control, Park-Neutral Starter Interrupt, Shift Interlock, AC Compressor Clutch Control, AC Req Idle-Up, AC Req Fan Control, Cruise Control, Vehicle Lighting, Donor Vehicle Gauge Clusters or any other donor vehicle features/conveniences.

You will be responsible for wiring your owner starter circuit with neutral safety and your own AC circuit if you are wanting AC. You can still leverage any of the factory AC components you’d like but it will be controlled separate from the harness. We recommend aftermarket HVAC, controls and dryer at least.

Gauges: We offer a 10% discount on any available Dakota Digital products with the purchase of our harness (contact us with specific product requests). The harness will retain the OBD port, so you can use that for your gauges or use some of the harness pigtails and add an oil pressure and coolant temp sensor to wire them directly. We recommend the latter if you’re planning to use the OBD continually for anything else because the signal isn’t always strong enough on an OBD splitter to run two devices. The CTS3 monitor can be used as a gauge cluster as well.

If you are interested in our standalone harness you can follow our ordering guide, purchase your harness modification a well as the ECM and TCM tunes and we can certainly get it running and driving properly for you.


Any attempts to make the above mentioned systems or features function are completely up to the customer and/or the installer.

Modifications will void any warranty or support, so it is crucial that you test start your setup with the harness prior to making any modifications. If you have not made modifications to the standalone harness, have proper tuning and are having issues with your test start, please see our diagnostics form.

Tuning Policy

Additional information

Weight 15 lbs
Dimensions 20 × 16 × 14 in
Harness Conversion

You will ship your donor, We supply donor

ECM Tune

You will ship your donor, Tune on new module

TCM Tune

You will ship your donor, Tune on new module, No tune


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