2000–2001 Ford Excursion 7.3L Engine Harness YC3Z‑12B637‑BA (CA Emissions)

Restore clean, reliable electrical performance on your 7.3L Excursion with this OE‑style replacement engine wiring harness engineered as a direct substitute for Ford part number YC3Z‑12B637‑BA. It is designed specifically for 2000–2001 Ford Excursion SUVs equipped with the 7.3L Powerstroke diesel, California emissions package, and automatic transmission, on engines built after 10/25/1999.​

This harness is configured to work with the California‑spec glow plug control module, not the federal‑style glow plug relay, so it is critical to match emissions, build date, and engine configuration before ordering. It features factory‑style connectors, correct wire lengths, and proper routing so it plugs directly into the original sensors, glow plug control module, and engine components with no cutting or splicing required. Ideal for fixing intermittent no‑start issues, glow plug faults, and random electrical gremlins caused by cracked insulation, chafed sections, or corroded terminals in the original harness, it allows you to refresh the engine wiring in one clean install instead of chasing individual circuits.​

Key features & benefits

• Direct replacement for OE engine harness part number YC3Z‑12B637‑BA

• Fits 2000–2001 Ford Excursion with 7.3L Powerstroke, California emissions, and automatic transmission

• Correct for engines built after 10/25/1999 (verify build date/engine tag before ordering)

• Designed to be used with a glow plug control module (sold separately), not a glow plug relay

• Factory‑style connectors and proper routing for plug‑and‑play installation with no cutting or splicing

• Helps resolve no‑start, intermittent stalling, glow plug issues, and sensor‑related electrical problems linked to 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 2000–2001 7.3L Excursion California‑emissions application matching YC3Z‑12B637‑BA specifications. The warranty covers failure due to manufacturing defects under normal use and does not cover damage from improper installation, modification, accidents, misuse, or use with the wrong emissions configuration or glow plug hardware. 

FAQ – 2000–2001 Excursion 7.3L Engine Harness YC3Z-12B637-BA

Q: What vehicles does this harness fit?
A: This harness is intended for 2000–2001 Ford Excursion SUVs equipped with the 7.3L Powerstroke diesel, California emissions, and an automatic transmission.​

Q: How do I know if my Excursion is California emissions?
A: Check the under‑hood emissions label; it will state that the vehicle conforms to California emissions standards. This harness is specifically for those California‑emissions trucks.​

Q: What engine build dates does this work with?
A: It is designed for engines built after 10/25/1999, so you should verify your engine build date on the engine tag or related documentation before ordering.​

Q: Does this harness use a glow plug relay or a glow plug control module?
A: This harness is designed to be used with a glow plug control module, not a traditional glow plug relay. The module must be present and is sold separately.​

Q: Can I use this on a federal‑emissions 7.3L with a glow plug relay?
A: No. Federal‑emissions trucks use a different glow plug system and wiring layout, so this California‑spec harness will not be compatible with relay‑style federal setups.​

Q: Do I need to cut or splice any wires to install it?
A: No. The harness is built as an OE‑style replacement with factory‑type connectors and routing, so it installs as a plug‑and‑play replacement for the original YC3Z‑12B637‑BA harness.​

Q: What kinds of problems can this harness help solve?
A: Replacing a failing harness can help resolve intermittent no‑start conditions, glow plug issues, random stalling, and various sensor‑related electrical faults caused by cracked insulation, chafed wires, or corroded connectors.