Hi, I’m Chris. Welcome and thanks for asking your question!
What brand alternator did you install?
Do you own a digital volt meter so I can help you diagnose this?
When testing voltage at the battery with not electrical loads on and the truck running what voltage are you getting?
With loads like the headlights, wipers, blower on what is the voltage now?
Yes I have ran into quite a few times where as it came down to a faulty PCM or wiring issue or alternator. no particular failure seems common. You need to run some testing on the wires using the below test, starting with section B.
Also if needed here is the wire diagram.
If you get held up on any of the tests, just let me know and I will help you through it. I feel your going to find this to be the PCM since it has been checked out already and they seem to be avoiding mentioning the computer controlled charging system.
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am hopefully helping you lower your repair bill or at least informing
you of the repair needed prior to getting it fixed.
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