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      Duramax diesel standalone wiring harness frequently asked questions


      Be sure to check out the harness form as well here: STANDALONE HARNESS FORM


      1. Do I have to use the Duramax steering column and/or ignition switch?

      ---No. With our standalone harness, you can use any ignition switch that you want! Keep the factory interior look of your old hot rod or classic truck by using the vehicle's original steering column and original ignition switch. All that is required to make the Duramax run is +12v ignition power. You can even run the engine on a toggle switch if you wanted to!


      2. Do I have to use the factory Duramax underhood fuse box?

      ---No. Our harnesses eliminate the big clunky factory Duramax underhood fuse box and replace it with a compact fuse and relay center that is only about 2" x 4" x 2" in size. The standalone fuse box is rated for underhood automotive use (splash-proof) and is made in the USA by Delphi. No junky generic fuse boxes!


      3. Which computers do I need to send in along with the harness?

      ---All that needs to be sent is the ECM (engine control module) and TCM (transmission control module). You do NOT have to send the FICM (fuel injection control module), GPCM (glow plug control module), or any other computers/modules.


      4. Which harness do I have to send?

      ---The only one harness that needs to be sent is the "ECM/TCM underhood harness". This is the harness that has the ECM and TCM connectors on it. It also has the long tail that goes down to the transmission. You do NOT have to send the "on engine" harness (ie, the harness with the fuel injector connectors), you do NOT have to send the dash harness, or any other misc chassis harnesses. NOTE: BE SURE THE HARNESS WIRING IS NOT CUT OR MODIFIED OR DAMAGED IN ANY WAY. If the harness has been cut/damaged/previous modified, there will be additional repair charges. Cracked plastic loom and unraveling tape is not a problem because that will be replaced, just be sure that the wiring itself is not damaged. We also prefer that the harness be fairly clean and not completely covered in grease/dirt/etc.


      5. What are my transmission options?

      ---You can choose from a wide variety of GM manual and automatic transmissions. You can run an Allison automatic, a ZF6 6-speed manual, a 4L80 automatic, a TH400 automatic, etc. With a special adapter plate, you can also run a Dodge 47re, or a Ford 4r100. Just be sure to specify which transmission you plan on running when sending us the harness. NOTE: extra cost may apply to change transmission options/modify the harness to use a different transmission.


      6. Do I have to use the factory Duramax instrument cluster?

      ---Your choice! You can use any standard aftermarket gauges of your choice (Autometer, ISSPro, etc). The harness will be setup with discrete speedometer signal and tach signal wires that output 4000-pulses-per-mile (speedo) and 2-pulses-per-revolution (tach). However, if you DO want to keep the factory instrument cluster, that is possible as well.


      7. Do I have to send the accelerator pedal?

      ---No, you do not have to send the accelerator pedal. Be sure to use the proper pedal for your year engine! 2001-2005 LB7/LLY pedals are different than 2006+ LBZ/LMM pedals.


      8. Can I use EFILive DSP-5 on the standalone harness?

      ---Yes. DSP-5 wiring can be integrated into the harness for easy installation of your DSP-5 switch. Our digital DSP-5 switches can be bundled with the harness for a discounted rate ($85, vs $149 normal retail)


      9. Can I keep Air conditioning working?

      ---Yes, you can keep air conditioning working, just apply +12v to the provided wire and the AC clutch will engage. Be sure to add a pressure switch to allow the compressor to cycle automatically.


      10. Can I keep cruise control working?

      ---Yes, cruise control is configured with simple +12v signal wires...you can mount toggle switches on the dash, or use the factory original cruise control switches of your antique vehicle.


      11. Does the harness include an OBD port?

      ---Yes, an OBD port on a long tail is included so you can easily mount the OBD port inside the cabin of your vehicle and use any regular scan tool to read codes and perform diagnostics on the engine.


      12. What fuse box is used?

      ---A compact fuse and relay center that is only about 2" x 4" x 2" in size. The standalone fuse box is rated for underhood automotive use (splash-proof) and is made in the USA by Delphi.


      13. What is the cost of the harness?

      ---Base harness price starts at $995. Additional options can be added for extra cost. See the standalone harness form for details. Shipping NOT included in price.


      14. How long does it take to have the harness converted?

      ---Actual time varies due to current harness workload and parts supply, it is best to figure on 4-5 weeks. Rush processing is available for extra cost.


      15. Can I start with a harness that was from an Express van or Kodiak medium duty truck?

      ---Yes. There is extra cost though, due to the additional complexities and work required to modify an Express van/Kodiak harness.


      16. Can I keep tow/haul mode working?



      17. Can I keep "tap-shift" working (LBZ only)

      ---Yes, you can mount up the factory LBZ shifter and use those buttons, or contact us for other tap-shift button options (dash mounted, etc)


      18. Can I have extra circuits added onto the harness for accessories?

      ---Yes, just tell us what you need and we will make it happen.


      19. What do I do about check engine light and glow plug light?

      ---The standalone harness includes wires for both check engine and glow plug lights. You can hook these wires up to any standard +12v indicator light and mount it on your dash.


      20. Can I add EFILive tuning for extra horsepower and better fuel economy?

      ---Yes, we offer full custom DSP-5 tuning and can pre-tune the ECM with our DSP-5 tuning. DSP-5 tuning is provided at a discount when bundled with a harness and digital DSP-5 switch!


      21. Will the neutral-start-safety feature still work?

      ---Yes. The neutral-start-safety and starter-interlock systems will work just like factory.


      22. Can I integrate and add wiring for headlights, brake lights, reverse lights, etc to the standalone engine harness?

      ---Yes, we can do anything custom for you! Additional cost will apply.


      23. Is the standalone engine harness difficult to hook up?

      ---Not at all! All wires are clearly labeled and tagged for easy identification. Just hook up battery +12v, ground, and +12v switched ignition power and you're off and running! All wires are color coded as well, for easy identification!


      24. What type of parts/materials are used in making the standalone engine harnesses?

      ---Only the best parts! We do NOT cut any corners or go any budget routes when we build our harnesses. The wire we use is automotive-grade TXL that meets all OEM specs for temperature resistance, oil/fuel resistance, and flame resistance. The wire loom that we use is automotive-grade OEM Nylon that is abrasion proof, and is resistant to fuel, oil, abrasion, and heat. The tape and wrap that we use is 3M Super 33+ industrial electrical tape, and on the parts of the harness that see the highest temperatures and abuse, we wrap the loom in genuine-OEM Tesa/Certoplast harness tape...this tape is made in Germany and is extremely tough. European car manufacturers have been using it for years on their automotive harnesses, and USA car mfg's have begun using it in the past few years as well. You can be guaranteed that your BT DieselWorks standalone harness will stand up just as well or better than a factory OEM harness.


      25. Is the harness easy to route, and how long is it?

      ---We include 12 feet of wire for the ignition switch, starter signal, check engine light, speedometer, cruise control, etc. The "interior" portion of the harness can be separated and disconnected from the engine portion of the harness via an OEM sealed Delphi weatherpack connector. This makes installation extremely easy, as you are only dealing with the harness one piece at a time, rather than the entire mess of wires! If you have a special application that requires more than 12 feet of wire, contact us.