front. Left.1995-97. Right.1995-97. A solid metal or plastic block with a threaded hole in the center which is used to tighten or adjust the Wheel Speed Sensor Wiring Harness. The main Harness for ABS system that would run from say the module, to the hydraulic control assembly, etc. There are usually separate Harnesses for the Wheel Speed Sensors. ASSEMBLY - Wheel Speed Wiring. System Main.