So here’s what happened. I have a GMC Safari. Two weeks ago I tried starting it and it was dead. I figured it was the battery. So the next day I jump started it and took it to a local repair shop. They told me it was the alternator. I told them to go ahead and put a new one in.
When I picked it up, it still had trouble starting, but I figured I just needed to let the battery charge. However even after driving it around awhile, I still had problems and the next day, it was completely dead. So I had to jump start it again and took it back to the repair shop. They said the battery had died, and so I told them to put in a new one.
It started up fine for the next few days, but last Thursday when I went to start it, it was again dead. I had to jump start it for the third time, took it back to the repair shop and told them it wasn’t getting any power. I asked them if perhaps there was anything wrong with the alternator or battery they put in. They looked at it and said they couldn’t find anything wrong with those two things and they said it was probably the starter.
But I’ve had a bad starter in the past on my other car, and in that case the lights and radio came on, even if the engine didn’t. That wasn’t the case here with the Safari. Nothing was coming on, not the dashboard lights or the radio or anything.
I told them that, but they said that a bad starter can sometimes drain the battery. I’m not much of a car person, but I still went :dubious:.
Anyway I didn’t feel like giving them any more of my money, so I just took my van home.
So does anyone have any idea what’s going on here or any suggestions for what my next course of action should be? And can a bad starter indeed drain a battery and if so how?
Sounds like you might have a short somewhere. Have you done any rewiring or install anything lately?
Bad starter drain the battery? Pull the other one it has bells on it.
In a word NO.
You have one of three issues
- A bad alternator or battery (my money would be on the alternator)
- An electrical draw in the system that is draining the battery. A draw can be intermittent which can make it hard to find
- Excessive resistance in the battery cables which causes a voltage drop and prevents the battery from charging fully. (not likely but possible)
I haven’t done anything like that myself. But the van is 17 years old, so it might have had something like that done in the past.
If I were you, I’d disconnect the battery every time you park it for a while. If the problem goes away, there’s a short somewhere.
ETA: You can get quick-disconnect battery clamps to make this quick and easy. They come in handy in a lot of ways, and are usually much better quality than the crappy sheet-metal stock clamps.
My vote goes to #3, particularly for a 17 YO vehicle. Probably the ground cable, from the battery to the frame. For less money than either the alternator or the battery, you can replace both the positive and negative. You can take a jumper cable and run it from the negative terminal to your frame and if that makes the lights work, it’s the negative cable.
You should get a battery charger, a small 2 amp one from WallyWorld goes for about $15-20 and they usually have a maintainer circuit that you can leave it on and plugged in and it won’t hurt the battery. Then, at the first sign of battery problems, you can fully charge the battery, since you cannot troubleshoot a problem like this without a fully charged battery. In my opinion, every car should come equipped with one of these from the factory so you can just plug your car in any time you need to. Such a device shouldn’t add more than $10 to the cost of the vehicle.
If the battery had a low charge and tried to charge it with just the alternator, well, you can fry a brand new alternator if your battery isn’t fully charged. The brand-new brushes need to wear in before they can handle full-output amperage. The mechanics that replaced your alternator should have known this and fully charged your battery before they replaced the alternator (maybe they did, I don’t know, but it seems odd to me that the battery would go bad if it could hold a full charge). Anyway, that is why I suspect a bad ground cable. It can be corroded on the inside and you can’t tell from looking at it. It happened to me once and I replaced the battery and starter before I did the jumper cable trick which saved me from replacing the alternator, too.
Good Luck,
excavating (for a mind)
I think both Rick and excavating have it right. It is unlikely to be the battery. Replacing a bad alternator with another bad alternator is possible but unlikely. You’ve got something else draining the battery. On a vehicle that age, the battery cables are an excellent place to start looking.
I’m not going to “guess”.
You can figure this out really quick and easy yourself, go get yourself a cheap multi-meter. Might cost you $20 on the high end.
When the van is running, you should get 14 plus volts (DC) across the battery terminals. If its less than that, you’re alternator is shot, or the voltage regulator is shot, but since I’m not a GM guy, I’m pretty sure your regulator is inside the alternator, in which case your alternator is shot. Its not unheard of for a rebuilt alternator to be crap out of the box.
I got 4 bad rebuilt GM alernators in a row once. They tested out fine on their equipment, put them on the car, and actually run them at speed, voltage would drop off, battery would discharge into the alternator and you couldn’t start the car. Cool the alternator off and it would test good again.
The battery should hold close to 13 volts just sitting there. Check it in the morning after the van has been sitting a while. If the battery was connected overnight, you can see if you have a drain on the battery, if it was not connected, you can see if the battery is crap.
Pretty easy to diagnose if you know what to look at, its a small simple system.
Guess time, even though I said I wouldn’t. You’re new alternator is garbage. Your mechanic is going to charge you for a new starter(and probably not replace it) and replace your alternator on warranty. He made money on your new battery, now he’ll make more.
This isn’t complicated, a “mechanic” should be able to figure it out really quick, if he can’t figure out how to use a volt meter, he’s an idiot and shouldn’t even be working on his own car. He would know if it was your battery, your alternator or your starter. We’re talking basics, stuff that hasn’t changed in damn near 100 years (alternator/generator… whatever)…
You’re getting screwed.
You would be surprised at the failure rate on rebuilt alternators. It is higher than you might expect.*
*Depending on where purchased, Way, way higher.
The battery, starter and alternator are items that can be checked. If the battery and alternator were bad, that should have been evident and both can go bad simultaneously. However, changing them did not solve the problem. At least it started for a few days. This suggests the battery held up a few days yet is being discharged when not driving. I believe you have a parasitic draw on the system. This can be found in minutes by turning everything off and connecting an amp meter between the battery and the car. The draw will show on the meter. Then disconnect various fuses until the draw goes away. That circuit is the culprit. It could be a stuck light switch, antenna, or whatever.
PS. There is always some draw on the system. Initially it can be up to 500ma and then quickly drop down to 15-40ma or more depending upon things like the radio and alarm system.
It looks like a 1994 GMC Safari does have an external voltage regulator, so that is something that you could have checked. A bad one would likely cause the problems you are having.
I have always been lucky then.
Start with the basics: Battery cables and voltage regulator. If the van is 17 years old, either one could be shot. If the battery cables are shot- often happens when the negative/ground to chassis connection rusts or the cable themselves wear- it would cause what’s going on with your vehicle. You can replace the battery and alternator three times over, but it won’t do you any good if there isn’t a decent connection and ground. They aren’t that expensive and they’re easy to do yourself (usually). Next, change out the voltage regulator. Again, not an expensive part and pretty easy, usually, for a do-it-yourselfer.
Moved MPSIMS --> IMHO.
Thanks for all your help. Took it to get checked out again. Turned out it was a faulty lock switch that was drawing power. I had had problems with the power locks not working lately, so I guess this makes sense.
Anyway they had to special order the part, but hopefully I can finally get this taken care of next week.
Only if the solenoid is stuck on, in which case the starter will try to operate, it will drain the battery in minutes, and it will be painfully obvious. I suggest switching to a shop where they know what they’re talking about.
Nailed it.
::: walks away humming “Nobody does it better”:::
So, is there no good way for a garage to test an alternator? A couple of years ago I had a situation a bit similar to Oscalo’s (except that the car started while being put on a tow truck…the fact that lifting the car changed things ultimately provided the clue as to what was wrong), and the garage declared the alternator to be the reason why the car, which had a fairly new battery, wouldn’t work. They replaced it, and I drove home. Next day, the car wouldn’t start again :mad:
In the end I paid for a new alternator, but the actual problem was that the shifter was not in good shape, teeth broken/missing or something. They fixed that without charging me, but I’ve always wondered why they didn’t know that there was nothing wrong with the alternator I had to start with.
Of course a competent shop can test an alternator.
Many shops either don’t have the proper tools or knowledge to do the test. It really isn’t that hard. But if you don’t know how or have the tools it is a lot tougher.
Yeah, when I took it to the new shop, I actually mentioned the thing about the starter.
They checked it out and said it was fine.