Alternator Problems

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Mar 29, 2025 | 09:37 PM

navigator9

Thread Starter

4th Gear

Joined: Mar 2025

Posts: 4

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Alternator Problems

Hello, 2015 F250 6.2L. Had a battery light come on. Replaced the alternator and it was good for about 300 miles. Battery light came back on. Replaced battery and alternator again. Light still on and alternator not charging. All connections look clean and secure. I am guessing the problem is in the control wiring from the alternator to the PCM. Not sure. Has anyone had this issue? Anyone have the pin-out for the PCM? EDIT: found the main alternator circuit fuze (175amp) had 637k ohms resistance. Replaced it and checks good.

Last edited by navigator9; Apr 1, 2025 at 04:36 PM. Reason: Solution

Mar 29, 2025 | 11:43 PM

ifrythings

Fleet Mechanic

Joined: Aug 2011

Posts: 1,576

Likes: 262

Use only OEM alternators on these trucks, the aftermarket ones are junk and leave the battery light on and only charge to 13.5v if they even work. These trucks are very picky on the alternators.