VM works normally, showing 13-14 volts with 1000 rpm. When parking lights and/or headlights are turned on, it pegs to the left (low) regardless of rpm.

Where do I start? Grounds? Relays? Alternator and battery are new.

I'm no electrician, but I have the usual collection of meters with mysterious scales and markings....

My first question would be where are you checking voltage at?

I would assume by VM you mean the dash gauge?

I would check the voltage right at the battery cable. (Not the post) Then switch lights on. More than likely, if it is charging, you have a high resistance connection somewhere. (Corrosion, etc.)

Use a handheld voltmeter, and after the battery, check it on the back of the gauge. Then check on the ignition swith, fuse box, etc. I would almost bet on the fusebox, or the relay board.

-- brett

Ahhh now i understand. For future reference VM or DVM is a handheld meter, Voltage gauge is what is in the car. Yes probably bad ground, anything else that would draw voltage to zero ( high current) would start wire smokin.

check for corroded cables (internal). do a voltage drop check on both positive and neg

Does your dimmer for the dash lights work? Mine doesn't and when I have the dash lights on, the gauge shows nothing. Don't ask me why.

On the battery positive post there are a few wires with large lugs bolted to the positive battery cable. Remove and clean them, and check for corrosion on both posts. These wires are the power leads for the main harness and feed the fuse panel, etc. If these are dirty/corroded, they will pass enough current during low load conditions but not under higher loads.
Tom

I would think you have the gauge wired wrong.

OK, the voltage gauge is what I meant. See, I SAID I was no electrician....

Thanks

You are the only one who came up with that, everyone else talked about grounds, but I've got good grounds for the lights, so I'm interested in more detail about your idea. Besides, It doesn't make sense to me that all the lights work fine. If it was a bad gound, I wouldn't expect that. Got any idea what might be wrong? It's a pretty simple setup, but I didn't wire it up so I'll start from scratch.

I should also note that when I turn on the lights, and the gauge is pegged, I still show 13 volts at the battery. maybe that doesn't matter? I confess to being less than bright when it comes to auto electrics.

If you are using a factory ground wire, it should be solid brown. Any other wire is wrong. Based on your description, I thing the ground wire you are using is actually a dash lamp wire. It would read as a ground with the lights off (your gauge works). But when turned on, the wire would become positive (your gauge stops working). This would not blow a fuse because the source power is the same and the gauge does not have a chassis ground. To test this theory, replace the ground wire you have connected with a seporate wire grounded to the vehicle chassis.

You sir, get a gold star. Dope that I am, i missed the obvious. Resorting the wires to the gauge solved the problem.

Thanks to all. On to the next....