Doesn't the PCM regulate the alternator on our Jeeps? I don't think their are internal regulators on our alternators and if that is the case it is usually either the PCM, or more commonly a wire that is intermittently shorting. I would carefully check the wring very thoroughly. If that comes up short I think the dealer can test the PCM but I have no idea of the costs. If the wiring comes up good it is more than likely a PCM issue.
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