On my 2017 F250, 6.7 diesel with 101,000 km, I got this message every time I started the truck. It came after some heavy snowfalls (Ontario, Canada). At the dealer the service manager immediately suggested likely a broken wire (he knew). The mechanic immediately went to a wiring harness over the front cross member of the frame. Yes, a badly corroded wire in the charging circuit. It was a sensor wire (white with red tracer). Repair wire and all is ok. The wiring harness is not protected very well. This will likely be a problem for others also.

 

Thanks for the info, any pics?

 

It is a known problem area, thanks for the reminder to others.

 

Its news to me, its why I'm looking for a few snap shots of the area mentioned.

 

It’s happened to me twice already. Mechanic said both times it was a wire that rubs on the alternator that caused the problems. Says they are to short and tight from the factory and he cut it put in a couple more inches. Hopefully it’s permanently fixed.

 

Sorry, no pics as I could not go into the shop.

 

Battery warning light was lit. Took truck into Ford where they found one alternator had shorted out. After replacement they then found the broken wire and repaired it.

 

Good afternoon all.
I see this is an old thread but have a few questions. I've got the "Service Charging System " warning that popped up on my screen. I checked the batteries (4 years old) and they originally read good. I cleaned the batteries and looked for the infamous broken wire from the alternator.
I didn't find any. When testing the batteries through a Charger with a battery check I was getting 12.5v disconnected. Then I checked the alternator while running from the same charger and I was getting 13.5 V. Then the truck died and would not get power through the system. I replaced the batteries, and the truck started right up. I checked the voltage from the alternator, and I was getting 13.5v again at both batteries and the charger showed the alternator was good. I checked at the OBD port and got 13.5-13.54V. I cleared the error for a few seconds, and it then the warning came back on. I have a single alternator and did not see any difference in V when turning on all of the accessories.
Now after describing all of that..... My questions are :
1. Is the alternator on the LOW end of charging and causing the issue? I've read that V should be 13.5 to about 14.5. Is this correct?
2. If there is a broken wire from the alternator to the connection at the firewall, would I still get 13.5-13.54 at the batteries and the OBD port? I wouldn't think so, but I'm limited on tools and knowledge when it comes to newer vehicles.
My experience would be normally on older vehicle to check fuses, voltage regulator, alternator, batteries.

Any help would be appreciated.

 

there are a few youtube videos on the subject wire and how to fix it,

 

Thanks speakerfritz.
I watched quite a few YTs going down the rabbit hole today.
I finally found one where a guy showed 13.5 v prior to finding a wire break. It showed a couple of specific areas where to look.
I’m going to climb back under the truck tomorrow and look again.

 

 

I watched this and one from 8 lug productions on YT.
The thing that has me perplexed is that I’m not pulling a code of P0620 off of the OBD. I have nothing at all for a charging system error. I’m gonna get up underneath again tomorrow before I take it in to a shop( last option). Just moved to a new area.

Thanks for all of the feedback. Either I’ll figure it out or bite the bullet.

 

At least my warning became very clear when I opened the hood...suicidal squirrel used his head to pop the belt off the alternator. LOL

 

Well , I went down the rabbit hole tracing things down. I jacked up the truck , pulled front wheels off, turned into a damned contortionist and a one armed paper hanger, found the infamous broken yellow wire, screamed profanities at engineers and wished them death by sodomy, finally spliced a 2” wire at the break, started the truck and within 20 damned seconds “ Service Charging system” .

Feeling defeated and in need of Bourbon at this point, I said “ Self , let’s check the ONB and see what the magic number is. To my surprise ……. 14.67- 14.7v. I cleared the errors “ still nothing about charging or the dreaded P0620. .My trusty battery charger said “ Hey dude, what about me ? “ so hooking up….. guess what ? 14.7 at both batteries.

Throwing a hand gesture at my truck, I said “Good night !” Tomorrow we will meet again . I buy you nice shoes , give you the best wine, talk to you nicely and don’t mention your age 215015 ish. It may be time to look for a new girlfriend ……….
JK. My Superduties have been reliable and some of the best trucks that I’ve owned. Just a little frustrated with the amount of effort and lack of working room on today’s vehicles. I’m a dinosaur and long for the days of 390 fords and 440 6 pack Dodges. I used to get dirty and greasy but now more than ever you have to be a Wiley Coyote Suer Genius to work on things.
sorry about the rant and hope that you had a laugh.