Ads See aftermarket wire harness for ls3 American Autowire $287American Autowire 510008 Power Plus 20 Circuit Wiring Harness$287Victory 50632701 $92Victory 50632701 OEM Wire Harness$92LS3 / LS7 MAF To LS2 $10LS3 / LS7 MAF To LS2 Harness Adapter$102007-2008 LS2/LS3/LS$6492007-2008 LS2/LS3/LS7 Engine Wiring Harness$649JEGS 10405 Universal $270Free ShippingJEGS 10405 Universal Wiring Harness 20-Circuit$270Free ShippingPainless Performanc$1,006 1Painless Performance 60524 Wiring Harness EFI Standard Length For Throttle By Wire Gen IV LS3 Engine 2007-Up$1,006 1Painless Performanc$524Free ShippingPainless Performance Products 10401 Pro Series 23-Circuit Wiring Harness Kit$524Free ShippingFAST 301972 Wiring $218FAST 301972 Wiring Harness, Xim For LS1 St And Alone$218 58x LS2, LS3, LS7 Stand Alone Engine Harness For E38 ECU There is no output wire for oil pressure or temperature gauges since the aftermarket usually supplies sending units and wiring for these. The harness will have provisions to plug in to the stock oil pressure and coolant temperature sensors on the engine for use with OBD scanners/gauges. Southern Performance Systems: Gen IV Wire Harness Kits All Wire Harnesses are tagged and come with instructions. All Custom Gen IV Wire Harnesses are professionally built to excede OEM standards. The harness shown on the page is an example of a LS3 with 4L70E setup.