Voltage problem
WHAT year?
What car?
Did it ever work "correctly"
WHat modifications have you done
What are you trying to fix?
In stock form these cars "Charge Indicator" will move around alot. typically at a stoplight you might even see it below center. when the turn signal is on it will bounce around.
This is mostly normal.
The indicator is displaying the current NOT the voltage. at low RPM the typical ALT will not produce enough current to satisfy the loads ( lights, radio etc.)
There are other things that can be in play here as well, bad connections, miswired connections.
as For tests, first we need to understand what is the real issue is
disconnecting the VR and if it stabilizes that means the cables and alternator are good I did that and it did stabilize
if you disconnect the VR the alternator will not output anything you will be running on battery alone.
