Oxygen Sensor Wire Harness Extension Kit. Installing Full length, long tube headers will locate the O2 sensors further away from the engine and the factory wire harness. These wire harness extensions will enable the sensors to be easily connected to the vehicle harness without the need for splicing or fabrication of any kind. These extensions are sold in pairs and feature factory connectors for a simple plug-in installation. Premium harness feature a heat resistant fiberglass sleave.