charging problem
I'll upload the photo of the meter while I digest what you've written. I appreciate the help.
Ok to do the two tests that I outlined, move the pointer of the switch to upper left, about 10 o' clock, and start on the 20V scale. If your don't read anything, switch down one at a time until you get a reading. HOPEfully, doing these two tests, you will end up in the 2 or even 200mv (200 millivolt) scale. A millivolt is one / thousands of one volt, so 200 mv is .2 volts, or 2 tenths of one volt.
still fuzzy on reading voltage from one ground (the battery negative post) to another (the mounting flange of the VR) Can you explain where the voltage would come from?
If the ground contact between the VR flange and the body or any other contact in that path between the battery post and the VR flange is bad, does a small amount of voltage backfeed from the VR to the battery post through the meter giving you some sort of a voltage reading? Is that what happens with a bad VR ground?
That is basically it. The VR draws current partly because of it's internal components "in operation." ANYTHING that draws current is capable of causing a voltage drop. Sometimes the drop is so small you simply cannot measure this drop. Picture in your mind a simple battery and light bulb. You have a light bulb connected by wires to a battery. Now remove one wire, and replace it with a REALLY small wire, that is REALLY long. Hundreds of feet long. NOW this wire, both because it is long and small, can start to have some RESISTANCE that we can measure.
Your multimeter DOES NOT draw very much current. This means that it does not CAUSE voltage drop in the kind of situation in which we are using it to measure. If you were now to take your light bulb, "in operation," with the hundreds of feet of wire, and were to hook your meter probes at each end of that hundreds of feet, you would read a small voltage. This hundreds of feet of wire, in fact IS a resistor. The current flowing through the light bulb causes the voltage to "drop" as it goes through the resistance of the wire
Your VR ground is the same. Let's talk "backwards"
Power comes from the battery to the VR IGN terminal, and operates the VR, which draws "some" current. Now it has to get back to battery NEG, but it CANNOT because there is a poor connection to ground---and on back--- to battery negative.. This RESISTANCE in the poor connection causes a small voltage to show up there right between the VR case and the battery.
To put this in EXTREME terms, if you were to remove the VR completely from the firewall, and "do this test"--------one probe on battery NEG and the other on the VR case----you would read FULL BATTERY VOLTAGE. This voltage then, can be anywhere from battery voltage down to zero ---- depending on "how good" the connection is between the VR case and the battery NEG
"Put one probe on switched 12V ignition, the other probe on battery POSITIVE."
"switched 12V ignition" as in the IGN terminal on the VR, correct?.
Exactly so
There are many terms "we" use for switched ignition. Ma calls it "IGN 1" on the diagrams, sometimes we call it "ignition run."
This comes out of the bulkhead from the switch, and depending on vehicle model / year and accessories supplies several things
ignition system
VR "I" terminal
Alternator field on 70 and later
idle solenoid on some cars (smog)
distributor retard solenoid on some (smog)
auto choke heater if used
and a couple of other smog "doo dads" on some models and years.
THIS voltage IS the operating voltage AND the "sensing" voltage for the VR. If "all this stuff" which it powers is low in voltage, the VR will "think" that the battery is low----and crank up the charging voltage.
IN A CASE where a resistance in the ignition voltage is LOW, a DIFFERENT way you can check it is as follows:
With engine running, "normal" at fast idle, IF the VR is working properly, the IGN terminal of the VR will measure right at 13.8--14.2 (14V) LIKE IT SHOULD
But if there is "drop" in that circuit, the battery running voltage will measure HIGHER than 14. This is because the VR is simply maintaining it's "setpoint" or "sense voltage" right at 14 just like it should. But because the HARNESS and wiring, connections, switches, are DROPPING this voltage, the alternator is actually supplying HIGHER than 14V "to the battery."