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HELP F350 with sudden electrical loss then engine shut down

23K views 8 replies 6 participants last post by  bigb 
#1 ·
Ok.... I think I wrote me first attempt wrong, I have an 2002 F350 with 7.3 that started with sudden electrical lost. The radio died and ABS light came on. After parking the truck for about an hour I drove it home, about 5 miles down the road. Lost electrical power again, then lost all gauges, then engine shut down like I turned the key off. After checking things over on the side of the road. I was able to restart the truck and drove it a quarter mile home and everything happened again. This time I heard a clicking or viberaring coming from the fuse pannel. I've checked fuses and such also battery cables. Thank you for any hel, I really don't want to tow the truck somewhere if I can fix it
 
#2 ·
Do you have a volt meter? A load tester would be even better.
Start by cleaning the battery terminals very well as well as checking / cleaning the alternator connection. Check the voltage of each battery individually (disconnected from the truck). If either is less than about 12.5, charge them (again individually) load test them if you have a tester (if you have a spare vehicle/spouse /friend available you can take them to an auto parts store where battery testing is typically free)
If all checks out reconnect everything and start the truck. Measure voltage at the alternator and at each battery (all 3 places should be the same +/_ 0.1) you should be reading between 13.6 and 14.4. If above or below this or if it fluctuates much then suspect the alternator.
Report back with your findings and we can go from there.
 
#3 ·
On the 2002 there is a small junction box located on the drivers side wheel liner kind of behind the air box, close to the fender. It is only about 1.5" long and 1" wide. There is a red cable coming in from the battery at the front and two gray fuseable links leaving out the back that provide all the power for your truck. This junction box is nothing more than a bolt and nut holding these three wires together inside a plastic box. It is subject to road grime and salt in cold climates, and will deteriorate and fail. I am 99 percent positive this is your problem.
 
#4 ·
An alternator gone bad and the batteries drawing down will cause all kinds of weird things to happen. Gauges, lights flashing, etc. Eventually the PCM won't have enough voltage to make the injectors fire, and the engine will shut down. I dodged that bullet on the way to work one morning, and had the wife bring me the spare alternator. The one on the truck was toast.
I'm guessing that's your problem, or at least high on the list.
 
#5 ·
Thank you for the help! I found the junction cable on the fender and it was lose, so I tightened that and found a lose ground under the dash..... I cleaned the battery connections and after all of that everything seems normal again. This is my first ford and while it sounds dumb I'm just not used to working on it yet. Thank you again for the help!
 
#6 ·
bigb - thanks for your post. My 2002 F350's electric power kept intermittently going out similar to what was described by nscovanner. The shop said it was the sm wire on the back of the alternator & replaced it but my problem continued. Saw your post & checked the junction box where the wires were completely corroded apart - pretty ez fix.
 
#7 ·
Glad it was useful, often there is more knowledge on the forums than some of the repair shops. We've been there, done that so to speak.
 
#9 ·
You'd be better off to start a new thread, this one is over 3 years old. And tell us what year your truck is and what all is has chip wise and what has been done repair wise so far. The year is most important as there were many electrical changes made in 2002, assuming it is a 7.3 Superduty.
 
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