When the main engine harness on an early 6.0 Powerstroke gets brittle, chafed, or spliced one too many times, you end up chasing hard starts, stalls, and random sensor codes. The Atlas Diesel Components 5C3Z-12B637-AA engine wiring harness replaces that worn assembly in one shot for 2004–2005 Ford Super Duty and Excursion trucks with an engine build date of 7/19/2004 through 11/4/2004.

Trucks built after 11/4/2004 use the later 5C3Z-12B637-BA harness. Matching your build date window is what makes it plug in correctly.

What you get:

• New Atlas main engine wiring harness assembly
• Direct replacement for Ford 5C3Z-12B637-AA
• Fits 6.0L Powerstroke F-250, F-350, F-450, F-550, and Excursion with engine build date 7/19/2004 to 11/4/2004
• Main engine harness only; injector and FICM harnesses are sold separately

Specs:

• Engine: Ford 6.0L Powerstroke diesel
• Engine build date range: 7/19/2004 – 11/4/2004
• Condition: New
• Cross-reference: Ford 5C3Z-12B637-AA, 5C3Z12B637AA, base number 12B637

A good fit for owners repairing heat-damaged or rodent-chewed wiring, or anyone tired of patching individual circuits. Many owners replace the FICM harness at the same time. Check the engine build date on your engine or door-jamb label. Trucks built before 7/19/2004 or after 11/4/2004 use a different harness. Verify fitment for your truck before ordering.