Hello, I have a 2017 f250 6.7 powerstroke
160k i recently developed the service charging system followed by illuminated battery light. The battery is charging 14.5 volts at battery engine idling. From what I understand the 3 wire plug on drivers side alternator has issues with the wires under oil pain breaking etc. Mine do not seem to be broke. I want to do a pin out test on it. On the alternator plug the right side has B+ constant verified from test light. Does anyone know what pins in pcm the other wires go to? I watched a video on YouTube and it was a 2011 Superduty so I don’t think the pin out is the same. Any help greatly appreciated.

 

did you disconnect the batteries and load test them individually?

 

Problem fixed. I pinned out the wires from alternator to pcm connector. Middle yellow wire was broke. Pulled harness and found coroded broke part. Spliced it together and still had too high Of resistance. I ran a new wire from break to pcm connector. Problem
fixed.

 

I had this problem and was going down the same rabbit hole as your are headed towards and found no discrepancies. as indicated in the AROD video, the problem was a thick wire that runs to a module close to the drivers side firewall. supposedly wire internally breaks down to an open circuit due to corrosion.... but...I think the wire is being used in an unintended current traqnsfer and the wire is melting. there are no breaks in the insulation.

in any event the wire has to be bypassed and mine was done under warrnty.

also, check your pax side battery for termical corrosion and stnd alone disconnected battery voltage....my pax battery was dead (2 years old and 10K miles) and I suspect the lack of a charged pax battery was a factor in the unintended current transfer that melted the subject wire.

 

Very good info. I’ve put 800 miles on mine since repair with no issues.

 

Nice! I am just tackling this problem. Did you find the PCM info or just test every one?

 

I pinned out the harness. On drivers side alternator plug. 3 wires on it. Far right should be 12v other two go to pcm. Plug on left side of pcm. Pin 53 and pin 14 go to alt plug. 53 is the yellow wire.