Good morning all!! I'm desperately looking for assistance! I have a 2012 F350 with the 6.7l. I recently had the battery light illuminating and dash lights all going out while driving down the road. I used my tuner to check codes and voltage. When the dash lights go out, including the radio and door locks/windows, I was showing 17+ volts. I double-checked voltage at the battery and was getting the same. I had the alternator checked on the truck and it failed the test. I replaced the alternator and had the same problem. I had the shop test the core and it tested GOOD off the truck. I swapped batteries with known good batteries and still have the same issue. I have been informed that the dash lights and all are going off due to a built in system that shuts these things down to keep from blowing - that is great.

However, what am I missing? I can't find anything online for overcharging. The unit bench tests fine. I believe it has something to do with wiring, but what? I can find a lot of posts about several wiring harness shorting/grounding out, but all those are related to under/no charge from the alternator??? I'm baffled what could be wrong that causing that high of an over-charge!!!

Anybody have any suggestions or experience with this?? Please help

Jeff Brown

 

Have you checked to see if any stored DTC's?

 

I take it the truck was running when you measured 17v at the battery. There must be a voltage regulator somewhere in the system to control the voltage the alternator puts out. Find the module that regulates the voltage. That’s probably your culprit. My other concern is what damage has occurred to the batteries or other components that may not have been protected from over voltage. Good luck with that one.

 

Battery will be nice and charged up, eh?

In the "good old days" unregulated charging voltages were sometimes the result from a corroded or loose aka "lifted" regulator ground. Everything needs to see the same ground potential or the regulator can get confused. Not sure how that squares but it's something to look at. Loose, missing or corroded ground straps, excess paint, can do strange things.

 

Good morning all. Thanks for all the responses. I do have a code stored - P0625 generator field/F terminal circuit low.
last night my son and I tore into it and we think we found the issue. There is a ‘trough’ that runs under the front of the engine by the flywheel that contains a bunch of wires and cables that are tied together using A LOT of zip ties. There was an 18 gauge wire almost corroded in half. As soon as we touched the wire after cutting all the zip ties off, it broke in two. I had seen this problem on another forum for battery light illumination. We are going back together with it this morning. Crossing my fingers there are no other connection issues.

 

The wiring in that location is a known weakness and has been the problem with other electrical issues.
Re routing or better protection helps.

The issue was the resistance factor. The voltage regulator was attempting to over come the resistance.

 

Thanks. With it being a known issue, do you know if Ford has changed the pathway in newer trucks? I’d hope so. Lol. The post I found the suggestion was from a guy that took it to a dealership to fix. After a new alternator, two new batteries, and a $1100 bill, they found the $5 wire issue.

 

don't know if it has ever been corrected, doubtful as that is probably the most efficient route during assembly.

 

That’s a shame that they can’t figure out a better route. The truck is fixed and running like a champ. Thanks for the help and explanations. It’s great to discuss and pass ideas between other people that experience the same issues.

 

Reps sent to the OP for updating the thread with the solution. Glad to hear it's working well now.