Hmm, so I have been trying to defeat the bouncing voltmeter for a little while now, but this time I was set out to do it right. A couple of years ago I had broken down while I was out of town and since no one has alternator connectors on hand for my model I had a cheap Radioshack electrical connection crimped onto the wire and it kept a surprisingly tight grip on the pin on the alternator. The 4 pin connection actually only uses the one pin, so it was an easy fix that lasted me quite a while. No one said it had to be pretty.

Anyway, so of course this eventually gave me problems as it went through climate changes. Especially after winter when it began to get warm again. So I assumed this was always the cause of my bouncing voltmeter. So in July '09 I had a put a new alternator and battery in when I rigged up this connection. So I wanted to finally have a stable 14 V and not have to worry about it, so I ordered a new positive battery cable (to alt and starter) and a new actual alternator connector replacement. When I took the current alternator off, the bolt was spinning so I grabbed another one under warranty replacement from Autozone. I soldered the connector onto the wire and electrical taped over the solder and installed everything.

Now the meter is much more stable, but it slowly climbs down at low speeds and idling, especially if high current accessories are on (AC, rear defrost, etc). If I'm going fast (40+) it stays pretty steady around 13.5 V, acceptable in my book. So the question becomes .. what else could be causing the drop? The ground connections looked clean from the battery to the block.

One thing I should mention is I did short the battery out for a second... It turns out you need to be a little more careful with replacement battery cables as they have more metal exposed than the original. So when I reconnected the negative terminal I got a firework show and a car trying to start itself. I electrical taped it up pretty well though and that is fixed. Not sure if this could have damaged the battery or not. It was only for a second, but I know that'* a heck of a lot of current. Fortunately I lived to tell the tale

Ready for suggestions

how low is it going, to come down some at idle is normal. do you have any extra acc'* like fog lights stereo etc.?

Your alternator could be going bad.

Just got a replacement alternator as a warranty replacement yesterday. The previous one was doing it as well. This one is actually more stable.

Immediately after I finished installing everything it was at a solid 14 V. Then on my way to Autozone to return the old alternator it trickled down to right at 12 V. This was with the AC and stereo on. Stereo is an aftermarket, but those things shouldn't draw much juice. When I flip the AC off it does bounce up some. I did have the thought that it could be a poor charge from the previous alternator and took it on the highway for 20 minutes. It seemed more stable after that, but still slowly dropping. I didn't wait it out to see how low it would go.

i wouldnt be worried if it was high 12'* at idle and 13'* when driving. you cant go by the gauge for accurate readings because its almost never right, so if it goes into the probably mid 12s on a meter something is wrong.

Yesterday it was right on the tick on the gauge which is just a hair above the red zone, I think that is 12.0 V if I remember correctly. Today I only drove it for 10 minutes, but it was low speed and I had accessories cranked couldn't get it below 13. Maybe it was just the battery needing a good charge. I guess we'll see next week.

hopefully thats all it is