The original coil harness has two issues one, the plastic coil plugs break from heat and age and two, the wire insulation becomes brittle and falls off resulting in a short circuit. This harness is made to replace the coil portion of the engine harness. You will need to cut the harness (12 wires) and install the plug that is provided. The new harness can then plug in to the original harness without messy wire connectors.