Ford H.E.G.O. O2 Sensor Harness Diagram M-12071-D302/H302 – Connectors & Wires

This document is an illustrated parts/wiring reference for a Ford H.E.G.O. (Heated Exhaust Gas Oxygen) sensor harness, part M-12071-D302/H302. The line drawing shows the physical routing of the convoluted (loomed) harness relative to the front of the engine, with four numbered connector callouts (42–45). A note specifies which harness part number to use by transmission type: automatic transmissions use E8ZZ-12A690-B (E8ZB-12A690-BA), while manual transmissions use E8ZZ-12A690-A (E8ZB-12A690-AA), and instructs the installer to discard the unused harness. A legend table identifies each connector and its wire colors: connector 42 mates to the main harness (LB/Y, P/Y, R/BK, W/PK, GY/Y, BL/GR, BK/GR); connector 43 is for the low oil level sender, marked 'Not Used' (W/PK); connector 44 goes to the left-hand H.E.G.O. sensor (GY/Y, BK/GR, BL/Y); and connector 45 goes to the right-hand H.E.G.O. sensor (GY/Y, BK/GR, R/BK). A reader can use this to identify correct part numbers, connector locations, and wire color codes when installing or troubleshooting the oxygen sensor harness on a 5.0L EFI Mustang-style engine swap or repair.