Intermittent problem has become more frequent. I think voltage regulator is failing in a weird way. For a minute or five a couple times per hour, all electricals pulse. I had my voltmeter-equipped usb charger in place today and when it’s good I see 14.6-14.7v. When it’s pulsing at maybe 5-8Hz, I see a min/max of 13.7 to 15.1.
I expect the regulator is in the PCM. truck is on its third alternator that I know of, year or two old. Could be poor response and lag in alt? Or bad pcm regulator?
Need to decide between throwing alternator at it or setting up an external regulator, I think. It’s irregular enough that it would be hard to sketch with a scan tool unless it was on all the time. The CTS insight sees a steady 13.0v at all times. I don’t know if it’s measuring, or polling ECU.