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Help 02 7.3 f550 starting problem

Discussion in 'Truck & Equipment Repair' started by 518Landscapes, Jan 30, 2012.

  1. 518Landscapes

    518Landscapes Member
    Messages: 43

    i HAVE A O2 F550 7.3 :help:

    This morning went to start to go on a salt run, and nothing wont start. only thing doing anything was the instrument cluster was flickering and making a buzzing grumbling noise, in the run position or start position. I drove this truck two days ago and parked it in the shop working fine:realmad:

    check and charge battery's OK
    Starter, new 2 months ago check OK
    key on or off no head lights, turn signal, hi beams etc.
    not getting power in cab it seems.

    Some times When you pull the key out of the ignition the truck electrical will stays on if not totally in the off position. so I was thinking possible ignition switch failure. Or bad ground

    If any one has any insight on a possible diagnosis it would be greatly appreciated:drinkup:
  2. Greenery

    Greenery 2000 Club Member
    Messages: 2,379

    I know you said you checked your battery, but that's what sounds like the problem is to me.
  3. 518Landscapes

    518Landscapes Member
    Messages: 43

    ya I know, I put new battery's in it from Napa today as well and the same result. Still no luck
  4. fordtruck661

    fordtruck661 Senior Member
    from CT
    Messages: 404

    your cables running from your batteries may be bad. Check to see if they are all corroded
  5. Plowtoy

    Plowtoy Senior Member
    Messages: 929

    Clean both batteries connections. Even if there's not much visible corrosion, I would clean them and dielectric grease them.
  6. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,738

    Drivers inner fender behind the airbox. There's a junction box that powers the cab pwr. An 8 gauge wire, and 2-4 wires branching off it..start there
  7. deicepro

    deicepro PlowSite.com Addict
    Messages: 1,124

    Mine does that, wiggle the battery cables....
  8. fordsuvparts

    fordsuvparts Senior Member
    Messages: 134

    There is a wire that connects to the alternator that has a fusible link that goes bad and can cause some of those problems. I would check all the connections on the starter and the starter relay on the passenger side inner fender right behind the battery. The cables can be corroded but look fine, check each ground and power connection, especially the battery cables you need to clean them very very well.
    Last edited: Jan 30, 2012
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,738

    Hey Ford,,I think you might be wrong. Not that I have seen a 550 in a long time,,but if its the same as my 350,,,there isn't a starter solenoid on the pass. Side fender. The truck gets its inside pwr from that pwr box on the drivers inner fender,,not the pass side.
  10. Snowdog22

    Snowdog22 Junior Member
    Messages: 28

    possibly the ECM which is located behind drivers front tire fender....mine did the same thing a few years ago. $300 at dealer and running again. Look for about 100 wires running into fire wall below and right of master cylinder
  11. Milwaukee

    Milwaukee 2000 Club Member
    Messages: 2,180

    Before throw any $$ down drain

    Find buddy with scanner that will work with powerstroke.
  12. A.M.Canfora

    A.M.Canfora Member
    Messages: 46

    clean all the cables it is probably a ground issue. The dim blinking lights and the buzzers sounding like there sick is a good indication. When you go to crank the truck is there any clicking noises?
  13. 518Landscapes

    518Landscapes Member
    Messages: 43

    OK, up date on the f550 after tracing the + wires from batteries. I found a bulk head connecting three wires behind the air box on the driver side inner fender, it is covered with a plastic cap upon removing the cap it was full of green corrosion this is a common problem on these trucks I guess. I Eliminated the box changed the terminals, bolted them together shrink tube and taped it good as new lights are brighter then ever had it running the same night.Thumbs Up Bad design in my opinion.

    Thank you everyone for the help:drinkup:

    dieselss you were right on the money with your diagnosis.

  14. dfd9

    dfd9 PlowSite.com Addict
    Messages: 1,475

    Too late, same thing I was going to suggest. Had this happen on 2 of mine last year. What a stupid location as well as totally unneeded connection for this thing.

    Another Ford engineer with cranial rectal inversion.
  15. dieselss

    dieselss PlowSite Fanatic
    Messages: 10,738

    No prob 518. Nice to share what I have found over the years. Glad ya got it fixed and working again...now,,,,just need snow