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F-250 Electrical and Transmission Issues (Water + Rat)

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Old Yesterday | 03:32 PM
  #21  
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Update:

I've not fixed it yet, but I think I have a good theory as to what is the issue. There is no visible rat damage to wires, not even the slightest. There is some accumulated gunk on the outside of some wires, but it just looks bad. Fuse 23 (Engine control - transmission) was found blown and that should explain the transmission issues, appears to have been overlooked by the mechanics. Fuse 40 for the Fuel Pump has been blowing repeatedly - once in the initial incident (mechanic also replaced a relay for fuel pump), and it blew also when I replaced fuse 23 just recently. 23 has not blown again. There was smoke coming from behind the fusebox after replacing 23, and I've found no burnt wires. That leaves dust, being burnt by whatever short circuit on 40, or something inside the fusebox.

The junction box got the brunt of the water ingress, and so it should have been obvious from the start that it is the source of all the issues. I've started trying to get it off, and I see dust even below the connectors in the back (not sure how that is possible, but will clean it).

Some questions:

1) The junction box power terminal has a long bolt with a nut that is not very accessible (covered by plastic on 3/4 sides). It is also stripping and stuck, plus the wire has no slack, so it must be removed to open it up. Should I buy some special tool to get this nut off, as the screw does not allow my ratchet attachment to reach it.

2) Are the connectors on the back of the junction box unique, such that I they cannot be put together wrong, or do I need to mark them?
 

Last edited by r254; Yesterday at 03:41 PM.
Old Yesterday | 04:03 PM
  #22  
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It is easy to say do this or that AND sometimes the That comes with added problems, so,,,,, unless absolutely necessary, the less you disturb, the better.

If you can , how about a spray bottle with isopropyl alcohol sprayed on the back of the electrical fuse panel ? That should clean up most water damage ,evaporate quickly and allow you to determine if it helped, what do you think ?
 
Old Yesterday | 04:31 PM
  #23  
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Originally Posted by hanky
It is easy to say do this or that AND sometimes the That comes with added problems, so,,,,, unless absolutely necessary, the less you disturb, the better.

If you can , how about a spray bottle with isopropyl alcohol sprayed on the back of the electrical fuse panel ? That should clean up most water damage ,evaporate quickly and allow you to determine if it helped, what do you think ?
It is an idea, but I still need to get it off to do that well. I'd feel better having a look inside, and I'm looking on ebay for replacements.


A very feasible repair, though time consuming.

I may not have been clear about the amount of water ingress, but it was a lot. YTD 67" of rain.
 

Last edited by r254; Yesterday at 05:10 PM.
Old Yesterday | 07:21 PM
  #24  
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Damage to the Junction Box pcb is catastrophic, including several missing pins and damage to at least one of the connectors.



This is the worst one, the rest look fine. It still seats itself, but I guess I need to buy the box with the pigtails.
 
Old Today | 11:53 AM
  #25  
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From the looks of that board, there is a larger problem than water damage.
Can't promise , but will try to look in my info to see what circuits might have been involved to burn it to that extent.
Maybe you already know, do you ,thanks.
 
Old Today | 01:04 PM
  #26  
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Originally Posted by hanky
From the looks of that board, there is a larger problem than water damage.
Can't promise , but will try to look in my info to see what circuits might have been involved to burn it to that extent.
Maybe you already know, do you ,thanks.
If there was a problem with individual circuits, then it would be protected by the individual fuses, but if there was a short circuit inside the junction box, then that would explain the burning. I don't see any damage on the wires, even though there is burning of the same connector.

I have a new fusebox on order, including new connectors.

I suspect the large burn is from the fuel pump (#40) circuit. A few other blown fuses on 23 and 7, among some minor and some where I swapped a useful fuse.
 
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