Battery or alternator

I have a 95 Chevy astrology van that I’ve owned for about a year. On occasion (about once a month) when I start it, the battery gauge stays in the red and all the lights are dim. After driving a bit I can stop the van and restart it, and the battery gauge normally shoots up to normal, and lights are all bright again. Don’t have any problems outside of that, until now. For the last 4 day, my battery gauge has refused to pop out of the red, and lights are always dim. I can drive for a couple hundred miles and nothing changes. Last night, as I left work, it ran like it has been with low battery and then just died. There is no clicking, no “whirring” sound the starter normally makes, the battery just died. I’m on a very small budget and can’t afford a shop, or both battery and alternator. What are your thoughts on this problem and where should I invest my money?
As a side note, battery cables and posts are cleaned off, and are bolted securely. Nothing loose and no corrosion.

To clarify above, I can afford either a battery, OR an alternator. Just not both at this time

remove and clean alternator terminals. worth a shot. sounds like bad alternator to me. you can pay a shop $400 to replace alternator. a used one is 50. a new one is 150? can you do it?

You may need both.

But first have the battery/charging system tested.

But what can happen is, if you ask an alternator to recharge a deeply discharged battery repeatedly, it can damage the alternator.


At first, I thought just a bad alternator, but continuing to drive with a bad alternator can kill the battery. And, as @Tester mentioned, a bad battery can kill an alternator. But, both can be tested, preferably out of the car, so that you could know for sure which or both need to be replaced. Given the age of the van, a wire or circuit problem may also be at fault.

You may need one, both, or neither. There may be an intermittent wiring issue, a failed alternator, a weak battery, or any one or combo of these. You need to have the systems tested, or learn how to use a voltmeter and read a wiring diagram and test it yourself.

Not to be snarky or anything, but what you can afford and what is wrong with your van are entirely unrelated.

1st - you need to charge up the battery. A fully discharged battery will die quickly. Borrow a charger if you have to.

2nd - check the belt that spins the alternator.

3rd - when the battery is fully charged, see if it can start the motor. It is a good sign if it can. Drive a few miles to someplace that can test the battery and charging system.

Running with dim lights means you were not getting much, if any, output from the alternator. The battery was providing the power until it fully discharged. That means the battery was OK at that point. If the alternator is driven by a “V” belt, tighten up the belt charge the battery and hope that does the trick.

Check and make sure the battery terminals are clean and tight. Take it to Advance or Auto Zone and they can test your battery and alternator for free.

From the way you describe the actions of the trouble it seems to me that the battery is okay. Even though the charging system has failed you are still able to continue driving for some time while the battery is discharging. I think you most likely will need to replace the alternator but the wiring to it could be the cause of the trouble. Make sure all of the wire connections to the alternator are in good shape and making good connection. As was mentioned, you should be able to have the charging system checked out for free at places like Auto Zone. Since you can’t gamble on what the cause of the trouble is, make sure proper testing is done first to locate the actual source of the trouble. You might be able to save some extra money by getting replacement parts from a salvage yard if you are really scrimping by.

I agree with cougar, but running a battery down totally does damage. It may still be usable if you put a charger on it, but it will probably have reduced capacity at best.

Based on your original post, I suspect that the field wire may have a loose connection in it, especially if it is a spade connector. This is at the back of the alternator and it is NOT the large wire that is screwed onto a terminal. This wire comes from the regulator, or supplies battery voltage to the regulator if the regulator is built into the alternator.

If you have an external regulator, it could be bad.

It could also be the brush in the alternator. On some models of alternators, the brush is easily replaced, on others it is impossible. A new brush would be around $10-12 if it is replaceable.

Started it up today, and it went right up to 14 volts. Drove about 60 miles and the voltage never dropped at all. Checked the posts, all securely fastened. Also checked all the wires on the alterator, and starter to be safe. Everything is tight and secure. Couldn’t pull the alternator out though to have it checked. (Not mechanically inclined)

My guess is your battery is on the fritz and isn’t holding a charge like it should. If I had this problem the first thing I’d do is remove the battery from the vehicle and take it to one of the retail auto parts stores that will charge it up and do a load test on it. Often they’ll provide this service for free. Or if you can drive the vehicle, you can leave the battery installed, they can test it that way.

There’s some risk analysis to consider here. If you remove it and just take the battery, you’ll know the worse that could happen if a newbie staff gets ahold of it and mixes the + and - leads, the worst is they’ll ruin a good battery, but the vehicle will be safely at your home.


That’s old technology.

You use something like this to test battery’s today.

The battery doesn’t require recharging to determine if it’s bad.

And it also tests the charging/starting systems.


And only $175, not bad.


You don’t need to remove the alternator to have it or the charging system checked out. It is better to leave it in the vehicle. Since things are now working okay this could mean the trouble is with the wiring to the alternator and the alternator may be okay. It is very important that battery warning light is working okay and turns on when the problem is happening. The light should also turn on with the ignition switch in the ON position, along with the other warning lights.

@Tester … thanks for the link. Sears is the place that I’ve used in the past to load test my battery and they use a small hand-held gadget that looks like that. But they always insist to charge the battery first for some reason, before they do the test. The staff guy there always tell me the charging will take several hours, so I leave the battery with them and go to a nearby restaurant and have lunch. Maybe it’s a ruse to bring business to the restaurant … lol … no worries, I enjoy the lunch there.

No George,

It’s not required to recharge a battery with these new battery testers.

That’s what makes these things so great.

Fast and simple.