Voltage Regulation

[wcdeane]

I seem to have a charging system problem. I ended up getting stranded on the highway the other night...again. Just prior to this happening for the second time, I had the alternator bench tested, and it passed...purchased a new battery, and tested the battery voltage at idle just before venturing out. It read 13.7 Volts at idle, so I thought I was OK. However, now after getting stranded the idle voltage now reads 11.8 Volts. It seems to be an intermittent charging problem.

Question: Which controls the charging rate/voltage...a voltage regulator in the alternator, or the ECU?

Any insights are welcome.

...Walt '91 SE

[deecee]

The Voltage Regulator.