They are completely plug and play with four wire hookup (switched power, constant power and ground connections required). Harnesses are designed with a sliding grommet seal and 4 - 5 feet of length from the rear of the cylinder head to the PCM mounting position under the vehicle dashboard.A sliding grommet seal allows for professional, leak proof installation. Harnesses are professionally constructed from Brand New GM Delphi Connectors and TXL (Polyethylene Cross Linked) High Temperature Wire to GM Specifications. Note that harnesses are for non-emissions equipped vehicles and do not include air pump or EGR provisions. The item "03-07 LS Vortec Standalone Wiring Harness Drivebywire With4L60E 4.8 5.3 6.0 Multec" is in sale since Friday, May 25, 2018. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts\Air Intake & Fuel Delivery\Fuel Inject. The seller is "maddogperformance" and is located in Brandon, Florida. This item can be shipped worldwide.