I believe behind the dash somewhere. Seems to me Ralph sent me a diagram a couple years ago. It was a grounding strap behind the dash a smidge to the right of the steering column. Can’t really get to it without tearing apart a bunch of stuff but what little I could see it looked real clean in there. Guessing it was a ground for the entire cluster.

 

Wonder if that might be a tad loose???

 

Very possible HY. That was also on Ralph’s suspect list. But if that ground strap were loose wouldn’t all the dash gauges be wigging out?

 

Maybe..... My guess would be the volt gauge is just more sensitive to various connections. Either that, or you got yet another 'iffy' alternator.

 

Alternator? I wouldn't be the least bit surprised. MY original alternator died 7-1/2 years ago with 165,000 miles on it. I replaced it with a reman from Mexico. That was 20,000 miles ago. Don't know if I'm alone but reman anything (and especially alternators) never made me feel warm and fuzzy. I did have Advanced Auto Parts hook up their magic box a year and a half ago. The box that grades the battery, alternator, and starter. They said everything was fine. I have a cheapo magic box myself and it indicates the alternator is fine as well. But seriously, how well do those magic boxes detect "iffy"? The guy showed me the frequency graph and it was pretty flat and consistent.

 

Testing the AC side doesn't really tell you what the DC side is doing..... Graphing DC output would be interesting to see. IS it really varying some? Or is it just the gauge being silly?

 

Would the tensioner be a suspect as well? Perhaps it's getting a bit sticky?? It's the original tensioner.

 

Don't think so..... Tensioner tends to just lose belt tension, and you get a squeal.

 

I may replace that alternator. Keeping an eye on it for now. Assuming mine is a standard 90 amp.

Don’t understand how I can improve or add grounding to the regulator case and get the gauge needle to steady up only to get a half dozen trips out of it before it starts shaking again. This has been the case a half dozen times or more. Makes absolutely no sense to me.

 

I would suspect that the problem lies elsewhere then..... Where though... That is a VERY good question.... Would be interesting to put an O-scope on the alternator output, and see what the waveform looks like. I would expect it to be relatively flat line, that varies slightly with engine RPM.