Custom Harness ULTIMATE + GM Gen4 LS W/Multec DIYAutoTune

Durable, custom harness with factory coil, sensor, power, ground and starter terminations for a General Motors Gen 4 LS motor with 58x crank sensor. Integrated Fuse and Relay Control Module Fuel Injector Branches equipped with GM Multec 2 Truck style connectors

Professionally engineered and easy to install, fire up your engine on day one! All wiring is composed of TechFlex woven, self-extinguishing wrapped hi-temp TXL and GXL automotive grade wire with OEM Delphi and TE connectors. Reach the battery under the hood or in the trunk with 4 gauge power and 10 gauge ground wires.

All relays and fusing live in a single, waterproof fusebox and the fuel pump wiring / relays / fusing is big enough for pumps that can handle 1000whp or more right out of the box (10ga wire, 30amp circuit).

Additionally, all of the available I/O of the MS3Pro are brought out in the harness to make expansion as easy as possible regardless of the featureset you're planning to use, allowing for killer features like traction control, bump box, table switching, flex fuel, and more. This harness was designed to add optional 4L60E or 4L80E automatic transmission control as a plug and play extension (add PN: MS3PH-TRANS_4L60-PKG or MS3PH-TRANS_4L80-PKG)
MS3Pro ULTIMATE GM LS 58x Plug and Play includes

  • MS3Pro ULTIMATE ECU (PN: MS3V-U)
  • TunerStudio software suite (installed/ copy on included 8GB flash drive)
  • USB and Serial communication cables
  • GM Gen 4 LS base tune(s)
  • Durable, custom harness with factory coil, sensor, power, ground and starter terminations for a General Motors Gen 4 LS motor with 58x crank sensor
  • Integrated Fuse and Relay Control Module
  • Fuel Injector Branches equipped with GM Multec 2 Truck style connectors

Required connections:

  • Constant Power
  • Constant Ground
  • Switched Power
  • Starter
  • Alternator light
  • Suggested extra connections:
  • Fuel Pump Power
  • Tachometer Signal

The custom MS3Pro 58x GM LS Plug and Play Harness is configured for a cable operated throttle body. The included connectors are set up for an LS1 style throttle position sensor and IAC valve. Four barrel style or independent throttle body setups may require modifications to the harness.

Note that the alternator connection is designed for high mount alternators such as Corvette and truck setups. Low mount alternator setups, as well as other aftermarket accessory drives that do not have the alternator high on the driver's side, require our alternator extension cable (MS3Ph-LSAlt).

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