Thanks - I do not own a test light, but if this isn't the dandiest reason to buy one, I don't know what is Wiggling the wire around didn't seem to do much, although, the connector attached to the B+ terminal feels a little suspect, possibly broken metal under the plastic sheath.Good information. Now, if you reconnect the red connector to the D+ terminal on the alternator, does the "G" light turn on when you turn on the ignition? If you tug gently on the PRP/WHT wire, move it around a bit etc, does the light flicker / turn off / turn on?
Do you own a test light? Something like this? Note that this is the kind that does not use a battery (the type with a battery looks similar, but is usually called a continuity tester). If you do, unplug the red connector from the D+ terminal on the alternator. Clip the alligator clip on the test light to the fat B+ output on the back of the alternator, and touch the tip of the tester to the D+ terminal on the alternator. The test light should light up, and if it does not you can be quite certain the voltage regulator has gone bad.
If the B+ wire were broken, would the result be as it is now, really low charging numbers and a dead 'G' light?
There's no heat shield near the alternator (original long since gone I guess). I was mildy concerned engine heat may damage the internal regulator. Time will tell. Thanks