94 Chev PU low voltage

I have the same problem with my 92 Safari 4.3. But it has a digital gage set. And most don't work. It could be the gage is off. My engine runs fine, but my gages indicate it is overheating with no oil pressure. The speedometer and the odometer, are the only ones functioning. Try a volt meter. It could be a cell is going in the battery, or the headlights could need replaced.

I didn't realize old head lights would do that. I'll swap them out and see what happens.

I think you need to check voltage across the battery terminals at hi idle with everything on. If you only have 12 volts and not 13.5 to 14.5 V, you need to replace the alternator. Make sure your belt is tight. Headlites don't need replacing if they aren't burned out. Good luck........Pete

I have a 99 for work I had the same problem with for years. I run flashing lights and CB all day long whether or not the truck is running. I was going through a battery almost every year. They just got weaker and weaker. I replaced three alternators. Always the same thing. Would start out over 14 volts, but after a short period of time, I couldn't run much without the voltage dropping. Finally I purchased an alternator from a different source. Now I get steady 14 volts again. The battery holds charge and strength just fine. The weak alternators were causing all my problems. Never occurred to me the cheap part (made in Mexico) would be bad. I had three in a row. Unfortunately, I can't recommend where to go, cause I don't remember where I bought the good one. Just wanted to say I think you can get crap alternators brand new.

I'll do it Pete, that would be the most logical answer. I had this problem years ago with a old Toyota pu, and it turned out to be a problem with the wiring harness. So I though I would check around, perhaps see if there was a problem area on Chevy truck around that period or something. But it does indeed seem to be an alternator problem.

You might very well be right, Sticks. I have heard a lot of guff about AutoZone rebuild items, but my mechanic always insists on them. I know I'm not crazy about the power steering pump they sold us. It doesn't work any better than the old one, but it doesn't make any noise.

I'll test the battery voltage with a Fluke, and that seems to check out, I'll just have to try another alt. from a different source.

On Aug 15, 1:21=A0am, "Tim" wrote:

First of all Get a good Digital voltmeter you can get them at auto parts stores don't be cheap. Run the engine and connect across the bat terminals and verify the reading on your dash gauge is correct. It should be from your description. If it is then make sure your battery is good. Have it checked and replaced if necessary. Once a good battery in installed see if you problem is better. If it is only improved or not better then problem is in the alternator. Yes they can fail right away if you load them too much the diodes get hot and leak current which means no charge the hotter they get the less charge you will get out of it. Eventually they fail. Delphi Alts are not too good. I have a 99 suburban it came with the small Delphi 105amp alternator it lasted 40K here in Austin.I bought a new one but I noticed also that it could not keep up with the AC and such at idle. Lets face it this is a very poorly designed system, small Alternator thin charge wires ect. I added an electric fan to the condenser for better cooling and the Alternator could not keep up with the extra load. The cure for me was to just upgrade to a 140 amp alternator. It fits right on the brackets but is bigger so I had to make a back bracket for it for extra support. The plug on the side of the Alternator is different so I had to hunt around and get one from a alternator shop. GM wanted $50 for it and on mine only one of the 4 wires is used. I also had t change the belt since this alternator is bigger. I did add an additional charge wire too since the original wire was too thin of a gauge for this application. Now My Volt meter is always 13.8 to 14.4. Even with AC full on the fan motor never slows down when I stop at a light.

The total cost was about $160 for everything. But mine is a 99 and yours may be different.Could be cheaper too. If you decide to just replace yours, always pick a good new one, it does not have to be a GM since we know some of them are not too good.

good luck

The total cost was about $160 for everything. But mine is a 99 and yours may be different.Could be cheaper too. If you decide to just replace yours, always pick a good new one, it does not have to be a GM since we know some of them are not too good.

good luck

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Thanks, I have had suspecisions about the battery, but it checks good at rest. I do have another battery I can try, might not hurt.

I'd recommend a good analog meter, instead. Analog meters are better for some troubleshooting because they are quicker and don't show transient fluctuations as readily. Though, having both is a better option since a digital meter comes with more functionality out of the box than analog. Check Lowes or Home Depot for digital meters. Hit Radio Shack for the analog.

Not a bad idea, I had been considering an analog meter because sometimes the digital are too sensitive. But this could be a good reason as well.

Make sure you test the battery first. My Safari headlights got dimmer and dimmer. I switched them out with Wall Mart specials. Been fine ever since. But that was due to cloudy glass, in front of the bulb.