F350 complete loss of electricity

You are correct. I just learned this from another source as well. I also finally figured out where all the fuse links are. They are all connected to the starter relay. All the fuse links appear OK - insulation is good and no stretching.

I do have multimeter.

You have double checked the batteries are good right? Got a toaster to test with? (better than nuthin! )

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Do not meddle in the affairs of Dragons, for you are crunchy and good with ketchup........

Then lets follow the circuits and see where this open is. For I agree with the others, it's likely a bad connection.

Check the battery itself first, poke the battery lugs with the meter leads and check for 12 volts.

Assuming you've got 12 volts in the battery, turn the headlights on (yes, I know they are dead).

Check the positive circuit. Red meter lead against the + battery lug, black meter lead against the + battery connector.

You should see nothing. If you see voltage, the circuit is open there.

Continue testing down the positive circuit, like to the starter solenoid and the main leg that goes up to the fuse block. Always keep the red meter lead against the + battery lug. You should see nothing. If you do, there is an open in the circuit.

Do the same with the negative or ground circuit. Black meter lead against the - battery lug, positive meter lead against the - battery connector.

You should see nothing. If you see voltage, the circuit is open there.

Continue testing down the negative or ground circuit. like where the ground lead connects to the chassis, and the engine block. Always keep the black meter lead against the - battery lug. You should see nothing. If you do, there is an open in the circuit.

I tried to find a schematic for the wiring on a F350 on the internet without luck. I did locate a partial wiring diagram for a F150 and the 175 amp Mega fuse IMO will not kill all power if blown. A digital VOM could read 12 volts if there is no load other than the meter. Since this vehicle has 2 batteries and 4 battery cables and Pete Q stated that all power is gone I would have removed each cable from the battery and observed for corrosion and would have done a continuity test on the associated wiring. I also would want to do some type of load test on the batteries.

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Agmantoo
If they can do it,
you know you can!

Problem found! And yes, all of you who felt it was a cable issue were right. To my own embarrassment I had missed checking conductivity in one wire in one of the plus battery cables. Last night I was playing with my voltage meter just like Fox described, and found an open circuit between battery plus and starter motor relay. Then further examination today revealed that one of the three wires in the left side battery plus cable - obviously the one that goes to the starter motor relay was damaged. And I had even inspected this cable couple times and decided that it is just a surface scratch in the insulation!!! Do I feel stupid now or what! It took me almost a week!!!!

Do I feel stupid now or what! It took me almost a week!!!!

Everybody that has ever worked on any thing has been there.

Hey, at least you got it and you learned a bit about your truck in the process. Sounds like a win.

you knew it wasn't much wrong,,,,after all its a F350.....with one of the best engines of all times

let the flames begin....

Congrats,that is great news ! Electrical problems can be very frustrating,often times it is something simple .

try working on chinese atv's ,scooters and dirt bikes. you transcend the feeling of stupidity very quickly. I am one of the few mechanics in my area that works on them with any degree of success.

You learned and it didn't cost you a small fortune at the mechanics. Great!!

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Do not meddle in the affairs of Dragons, for you are crunchy and good with ketchup........

New battery cable is in place and everything is working again. Now, can't wait that blizzard to get here...