Cranks, no start. Wiring all messed up?

Tiny
RSFRANKLIN
  • MEMBER
  • 2006 FORD F-250
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
Bought with no starter. Got starter - wiring all messed up. Rewired both batteries, starter, alternator. Still not turning over. Changed relays and fuses, no change. Changed coils and spark plugs, still no change. Had one battery. Got second - cranks a few times, no start. Fuel pump engages. Fuel filter, unsure. We think that maybe we dont have the starter, alternator and batteries connected in the correct order.

we cant find a definite wiring diagram online and Chiltons has us confused on locations!

the truck is gas powered. Not sure if its 5.4l or 6.6l.

we have been at this dang super duty for almost 2 WEEKS! And YES. WE HAVE SEEN THIS TRUCK RUN. So we know the truck CAN START!

We will attach a video later today - we are just dang frustrated at this point!

any advice you may have, or directions you can give are greatly appreciated!

Thank you guys!
Tuesday, December 9th, 2025 AT 1:46 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,217 POSTS
No problem, I can help you fix it. So to be clear the engine is cranking over (starter) or the engine is cranking over but not starting, please upload a video it will help us. It is probably a 5.4 liter engine btw. I could be the starter relay is not working but here are the wiring diagrams so you can double check the repairs to the starter harness. Also, please go over this video as well

https://www.youtube.com/watch?v=6YRW8fyNudY&t

Check out the images (below). Please let us know what happens.
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Wednesday, December 10th, 2025 AT 10:42 AM

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