Engine wiring harness F81Z‑12B637‑EA for 1999.5–2001 Ford 7.3L Powerstroke Automatic FED emissions

Restore factory‑level reliability on your late‑OBS/early‑Super Duty 7.3L with this OE‑style replacement engine wiring harness, built as a direct substitute for Ford part number F81Z‑12B637‑EA. It is designed specifically for 1999.5–2001 Ford F‑250, F‑350, and F‑450 trucks equipped with the 7.3L Powerstroke, federal emissions package, and 4R100 automatic transmission. This harness fits trucks with a build date of 12/08/1998 or later and engine serial number 869,813 and up, ensuring the correct connector layout and routing for this mid‑cycle configuration.​

Configured for a traditional glow plug relay, this harness matches the federal‑emissions glow plug system used on these trucks. Pre‑terminated, factory‑style connectors and proper wire lengths allow you to plug directly into the original sensors, glow plug relay, transmission‑related connections, and engine components with no cutting or splicing. This makes it an ideal solution for intermittent no‑start conditions, electrical gremlins, and glow plug issues that stem from brittle insulation, chafed sections, or corroded terminals in the original harness.​

Key features & benefits

• Direct replacement for OE engine harness part number F81Z‑12B637‑EA

• Fits 1999.5–2001 Ford F‑250, F‑350, and F‑450 7.3L Powerstroke with federal emissions and 4R100 automatic transmission

• Correct for trucks built 12/08/1998 and later with engine serial number 869,813 and up

• Uses a glow plug relay configuration (not for California‑emissions glow plug module trucks)

• Factory‑style connectors, correct wire gauge, and proper routing for clean, plug‑and‑play installation

• Helps resolve no‑start, intermittent stalling, glow plug faults, and sensor‑related electrical issues caused by failing original wiring​

Warranty statement

This harness is backed by a limited 1‑year replacement warranty against defects in materials and workmanship when installed on a correct, stock‑configuration 1999.5–2001 7.3L Powerstroke federal‑emissions truck matching F81Z‑12B637‑EA fitment (including build date and engine serial range). The warranty covers failure due to manufacturing defects under normal use; it does not cover damage from improper installation, modification, accidents, misuse, or use on incorrect/emissions‑mismatched applications.