Car is a '96 Formula.

Today I noticed the volts gauge swinging from just to the right of the 13V hash mark, to the yellow on the left side. It would stay on either side for about 20 seconds before swinging to the other side. Sometimes it would stay right on the 13V mark before swinging to one side or the other. Didn't make any difference if the lights and AC were on, as it did the same thing. Haven't broken the multimeter out yet, but was wondering if it was likely to be the alternatof.

 

Probably so. You might want to have the alt tested.

 

Thanks Shoe.

Well, the batteries in my meter are dead, and I don't have any for replacement. I put an old, old analog meter on it, that doesn't use batteries, and couldn't see the fluctuations on it. However, I will get the system checked tomorrow.

 

My guess is the alternator. They have regulators inside them that should keep the voltage pretty normal, if they start to go then you'll see swings in voltage.

Of course it could be a loose wire, broken wire grounding or some other issue too.

 

I may have dodged a bullet. Decided to check connections and grounds, and the first one I checked was loose. It happened to be the cable on the back of the alternator. After tightening, gauge was functioning properly. I did take the car to Advance and Autozone, and the charging system checked out as being OK at both places.