Overcharging Help needed (74 scamp)

THIS SOUND LIKE MY FAVORITE PROBLEM which is very simple in nature, sometimes difficult to grasp and usually simple to fix

HERE IT IS

VOLTAGE DROP in the HARNESS AND SWITCH AND TERMINALS along the path from the battery to the VR and that also includes the GROUND side of the circuit

HOW TO troubleshoot and fix:

1....Turn the key to "run" with engine stopped. Stab one meter probe into the top of the POS batter POST. Connect the remaining probe as close as you can get to the VR IGN terminal (blue). If you can't do better, connect to the "key" side of the ballast. You are hoping to read very little the lower the better. Anything over .3V (3/10 of one volt) you need to investigate and fix

If you don't quite understand this, measure the two voltages to ground. IE with key "in run" measure battery POS voltage to engine block, "note" and read key side of ballast to engine block, and subtract the readings. Same reading as above^^

One way to fix voltage drop on the hot side is to use a relay to feed the ballast resistor and VR. Electrically cut the (normally) dark blue "run" line coming out of the bulkhead. Use the bulkhead end to trigger a relay. Feed the relay off the starter relay "stud" through a large fuse or breaker. Connect the engine bay end of the wire you cut to the siwtched contact of the relay.

2...GROUND. With engine running on fast idle to simulate "low to medium cruise" RPM, make reading first with all accessories off, and again with lights, heater, etc running. Stab one probe into the battery NEG post and the other into the metal mounting flange of the VR. You are hoping, again, for a very low reading, ZERO volts is perfect. If you read ANYTHING improve the grounding from battery NEG to the body.

Remove VR and scrape around mounting bolt holes, remount with star lock washers. Consider adding an eyele-to-eyelet "starter" cable from the driver side cylinder head to the firewall, there are bolt holes on the rear of a v8 head, and the master cylinder studs are a good point on the firewall. You are on your own on an slant 6