12 V DN50 Nervous VM Needle

[gus]

I finally solved this problem after almost five years of a wildly nervous VM needle. This thing drove me nuts!

The voltage at the VR P terminal was only 9.75 when it should have been batt voltage. I jumped this directly to the batt at the end of our last trip to make everything work but the needle still varied.

Since this is only a single #8 wire directly from the alt + terminal with no intermediate connections it is a mystery to me why it caused this problem?

I found an interior lighting solenoid next to the VR with a buss within 0.1V of batt voltage and connected that to the VR P terminal.

Now the VM needle is solid as a rock, the lights don't flicker, my BU monitor doesn't flicker and I can actually read the system voltage.