Doubtful it is the regulator but it COULD be. Disconnecting will likely prove nothing
What do you mean "the light?"
Please read the mad article.
"What is worth a try"
DISconnect the battery positive clamp and lay it aside "safely"
Connect a "big" say, no12 made up alligator clip wire or jumper cable, etc, and jumper it from the battery positive post to the alternator output wire. Be careful and wrap the main battery cable in a rag, etc, "it's hot."
Now clip your voltmeter onto the main (disconnected) battery clamp
Clip the other wire to the alternator output connection
This is going to measure voltage drop in the "path" from the alternator to the battery connection pont
Now turn on as much load as you can.....stereo, heater, wipers, headlights.
Read the meter, on low DC volts, I would expect no more than 1/2 volt or so. If more, you surely have a bad connection in that "path."
This can be VERY difficult to run down using the alternator "running."
This is because let's say there IS a bad connection at the bulkhead connector, or at the ammeter.
As the connection "makes and breaks" the regulator in the alternator "hunts" and surges and screws around, trying to keep things on an even track. The voltage surges up and down, and this can "hide" the problem
Alternatively, if the problem IS in the alternator................try this..............
make up a (at least temporary) BIG wire from the alternator output to the main battery stud on the start relay. Use no10, minimum, maybe two or three no 12 in parallel, or larger.
Run the car. Problem still there? (The ammeter will not show this at this time) Monitor battery voltage at the battery.. NO? then it's a wiring problem, as above
If it IS still there, it is surely an alternator problem
Whatever else you do, please READ the Mad article I posted.
