99 Chevy 4WD Battery Warning Light- System checks ok?

Well, from an intermittent troubleshooters perspective, I'd have someone observe the light while I went under the hood and jiggled some of the harnessess near their connector blocks and also the individual wires in the areas of the alternator and battery to see if the light does its thing. Take the back of a screwdiver handle and tap around. Heck, you might even want to make sure all of your fuses are pushed in good and tight while your at it and jiggle those harnesses as well.

You could even have loose connections on the very sensing circuit itself, or a malfunctioning sensing circuit when it heats up. Id need to refer that to specific Chevy techs on that model. I dont know if running a code reader would give you any more clues but it couldnt hurt.

Well I made it back from Michigan ok 1,100 miles round trip. But found out with the headlights on, no Battery Warning light? I'm convinced this is where to start checking. Reminder that the voltmeter never drops below 14.6 or so when this happens.

Where can I get (buy) a detailed wiring diagram for this model? I don't have a problem with electrical troubleshooting now that I'm back in my shop with tools and a meter.

But I thought I'd check with the Experts here first to see if this is (yet) another GM truck problem?

This Group has helped with a couple other problems in the past and I really appreciate it. Thank you. B.G. in Iowa

cory wrote:.

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Suggestions..?? Any..?? ok..... here goes....

If it, and I do quote, "NEVER".....goes below 14.6 vlts when this happens, then maybe you should look for a possible overcharge situation instead of an undercharge situation.

~~QUESTIONS~~ (out of curiousity)

Why was the battery replaced?

Why was the altenator replaced?

Are you measuring the 14.6 vlts at the altenator or the battery, or both?

~:~ MarshMonster ~suspects a ground problem~

Hmm never thought of the too high a voltage, but I thought the light was for low or no change. Anyway, Battery warning came on with old alternator -- once-- and about two months ago. I replaced alternator as a PM measure it had 79,000 miles. This was first long road trip since.

Battery was replaced when on the road at a GM service shop, mechanic said tester showed a bad cell (3 year old Exide), but rest of system checked ok and confirmed my Fluke meter reading of 14.6 VDC at battery and alternator, engine running at idle. He seemed to think the reading was normal.

Needless to say.. the new $138 (installed) Delco battery did NOT fix the problem. Thanks again for your reply and suggestion to check the grounds... I will do so. BTW Chilton or Haynes book for best detailed wiring?

======== ======== MS, a link for you.

~:~ Marsh ~doesn't care for Chilton or Haynes~