LWN (2.8L) Custom Standalone Harness/Solution


DmaxSwap.com has worked to develop the cleanest solution for wiring your LWN 2.8L 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, a new ECM, ECM tuning and test starting the system. Additionally you can select the option to purchase a donor harness.

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

** At this time we can only use 2016-2018 LWN donor harnesses.



The DSP-4 tune is built with 4 power levels. The power levels are customized based on the information provided in our Tune Request Form. Below we’ve provided a rough idea of the output and purpose for each tune. Power gain will be ~50hp without supporting upgrades, with ~15hp increments on each of the tune settings.

The tune settings are as follows:

  1. heavy tow tune
  2. light tow
  3. optimized stock (improved fuel mapping)
  4. street/race performance (depending on supporting mods)

All DSP-4 Tuning include the 4 position DSP switch and anodized aluminum knob with label ($50 value)

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.

LWN Tuning Policy

Additional information

Weight 10 lbs
Dimensions 20 × 15 × 6 in
Harness Conversion

You will ship your donor, We supply donor

ECM Tune

DSP-4, Single Tune


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