Z71-Guy

Hi Gang,

Got a strange thing going on with my voltage meter that just started. (1991 Silverado K1500 4x4, 5.7 liter)

My battery is fully charged and the alternator in the truck is roughly 6 years old. It’s a good, quality alternator, not a Chinese knock off.

A few days ago when I started the truck the volt meter needle was just a few points to the right of the red section and the battery light came on, after driving for a mile or so the battery light went off and the needle jumped back to where she always sits (right in the middle).

Yesterday the needle & battery light did the same thing and I just left her alone overnight. When I went to start her up this morning the needle was still near the red section and the battery light was still on but then out of nowhere (as she was idling, warming up) the needle "abruptly" jumped back to the middle and the battery light simultaneously went off.

It jumped quickly (not gradually) giving me the impression that all of this is some type of intermittent short or bad/loose connection.

The battery cables are tight and the negative battery cable has some slight oxidation where it attaches to the block, but it’s not completely green.

I’m pretty certain that I don’t have a bad battery or dying alternator.

I have a voltmeter but I can’t find the damn thing at the moment and I was just wondering if any of you guys have ever encountered something similar to this.

I did a search on Google and apparently the voltmeters on these trucks are prone to jump around and do weird things, but the electrical system on this truck was just about completely redone 4 years ago and she runs like a brand new truck with no issues, and she's never given me weird electrical issues up until now.

Any & all thoughts are welcome, thanks in advance…

Gumby22

The cluster is certainly suspect.

The easiest test is to find that damn voltmeter and run leads from the battery or alternator into the cab so you can monitor the voltage directly.

A relatively quick test for the gauge is to remove the lens and manually sweep the gauge with your finger - if it feels like it’s grabbing or choppy, the stepper motor needs replacement. If it’s smooth, the cluster could still be the issue but it’s isolated to the circuit board and contacts.

I understand your confidence, but it also wouldn’t hurt to test the battery and alternator, just to be sure. I’d recommend taking the alternator to an auto-electric specific shop. All parts fail for a variety of reasons and age (or cheap knock off parts) isn’t necessarily the defining factor.

hanky

For what it is worth,

Looking at "Connections" does nothing, they should be removed , cleaned and reinstalled , then you can be sure there is no problem there.
The better way to check voltages is to check the circuit under load.
For example ,that means if you are checking battery cable connections you should have your meter set to read on the lowest scale measuring the voltage drop across the cable and the connections with the system under load as in operating the starter motor. It is called voltage drop testing AND is the only real way to determine if there is any connection problem there. It is not difficult to do , and there are many videos on how to do this.

Z71-Guy

Thanks guys,

I'm going to look into and do all of the above this weekend, appreciate the replies & help.......