Alternator overcharging
Not sure an alternator can overcharge. The voltage regulator's job is to limit the voltage it receives. Sometimes you will find a bad VR, but usually you will find it is not grounded well enough. I typically run a new ground wire rather than relying on VR to body ground. Also, virtually every Mopar I own had worn VR mounting holes and the VR doesn't mount as tight as I would like.
I think that's only approximately correct;
as I understand it;
the VR reduces the fieldcoil strength in response to the voltage it is reading on the sensing wire. If the sensing wire voltage is low, it increases the fieldcoil strength, by grounding it. The Alternator immediately goes to WOT. The VR sees the sensing voltage going up, past it's internal set point, and throttles back the fieldcoil by opening the circuit, and the alternator stops charging completely,( well not completely completely,lol) . This cycle happens IDK how many times per minute, but the battery sees the average of WOT and way less than WOT, as this is going on; which is supposed to be about 13.2 to 14.2 on most systems, GMs not included; they run closer to 15.2.
If you momentarily ground the green wire coming out of the fieldcoil, you will see what your alternator is capable of putting out, with whatever battery voltage is coming down the blue wire, and at idle. This is called full-fielding. You will probably see the 17.3 that was listed in post #1. The VR was full-fielding. The only way it can do this is if the ground back to the Battery is 100% A-OK. If the ground was open circuit, it would not charge at all. If the ground was poor, anything can happen, so you always start by proving the ground, when diagnosing a low-charge. Not so with a 17.3 charge rate; that is about max, at idle, with a fully charged battery.She's stuck on WOT.