This product is NOT compatible with early style 99-02 DBW systems using an electronic throttle body with a large 2-pin connector motor and plastic base TAC module. You MUST use a throttle body and compatible pedal from 03-07 and a TAC module PN 12573059 with a metal mounting base.
 
Ditch that filthy, questionable factory harness for a new-from-scratch standalone harness from LS Harness Connection! Our standalone harnesses ensure you only have the wire you need for the cleanest installation and use new materials to prevent those pesky electrical gremlins from showing up.
 
This harness is for use with the P59 PCM which can be identified by the photo above, and its “Blue/Green” labeled connector ports. The harness is built and tested using PCM ending in 6242 and as such, that model is suggested for use for best compatibility and their widespread tuning configuration ability, but other PCM models have been used with success.
 
If you have a Gen 3 (1999-2007 Classic) 4.8, 5.3, 5.7, 6.0-liter LS/Vortec engine or custom build using a 24x crankshaft reluctor with a 1x cam reluctor and are using a manual or non-electronic throttle body with a 4L60E or 4L80E electronic automatic transmission, this is the harness for you!
 
Constructed of all new materials and connectors, LS Harness Connection helps you replace the junky, heat-cycled 20-year-old harness that may or may not lead to electrical gremlins and poor performance. The harness is built and situated for not only an easy installation but a clean appearance as well.
 
The factory harness crosses over the top of the intake manifold which leaves an unsightly mess in many LS swaps. LS Harness Connection harnesses come from the back of the engine and split to both driver and passenger banks with enough slack to tuck the wiring in between the fuel rail and intake to ensure your wiring is safely out of the way, and out of sight! Factory positioning also places the large bulky engine computer right up front for all to see – LSHC harnesses route the PCM to the passenger firewall where you can mount it on the firewall, fender well, or inside of the cabin under the passenger dash area.
 
All harnesses come standard with an installation guide for easy installation, and you can opt to have labels added to make the connection process even more simple! Connection to fire is as simple as connecting power, ground, fuel pump power, and ignition wire, and all standalone style harnesses include loose wiring for integration to the swap vehicle. Each harness comes standard with its own power distribution block to provide power to all things LS engine and transmission to ensure you are getting good constant power distribution to the powertrain you just installed.