1993 Saturn s-series new alternator, but won't stay one


My boyfriend is outside trying to fix a 1993 Saturn Saturn S series for a friend of mine. It kept dying and draining the battery, so he replaced the alternator. However, it will now charge, lights will flash, then it dies. He thought he found a short, but fixing that wire didn’t help. He can’t find any shorts and says the only way to fix it might be to replace ALL wires under the hood, which wouldn’t be worth it considering how old the car is. Any other suggestions or thoughts on what this could be??

The vehicle has the side mount battery cables.

Have him remove both battery cables from the battery. On the positive cable have him peel back the red rubber cover to expose the two terminals. If a lot of corrosion is found on the terminals that’s what’s causing the problem.


Thank you Tester. He said the battery cables are brand new… he bought them with the new battery. Any other thoughts, other than maybe it’s a lemon alternator???

PS - It stays on for 10 minutes after jump, then dies… brand new battery, alternator, battery cables… flashing lights on dash, no short identified…

You need a voltmeter to see what’s going on with the battery after the jump. The battery may be trash.

What light(s) is/are flashing on the dash?

insightful, thank you… it’s a second new battery though… / Keith, I didn’t see them but both my friend and boyfriend said the whole dash was flashing like there was either a short or a loose wire connecting and disconnecting. It’s just that he couldn’t find a short when he tested for one… or a loose wire.

There’s a fusible link between the alternator and the battery.

If the link is burned the alternator won’t keep the battery charged.

Follow the large wire off the alternator to the battery, and where the wire gets thicker is the fusible link.


Thanks Tester. He thought that’s what it was and followed the wire from alternator to battery and found nothing wrong… This car’s alternator was so hard to get out (tire and many other things had to be removed) and the only thing left he can think of is that the new alternator is bad so he wants to take it out and try another new one…

Your BF sounds like a great guy, but he’s guessing about what’s wrong. He should solicit help from a friend who knows cars and has the knowledge and equipment to test the battery and some other systems. The battery may be toast, the fusible link may be blown (they’re supposed to bubble the insulation, but they don’t always, and it can be blown but look visibly good), and the problem might be elsewhere entirely.

It will definitely not be worth it to just start changing wires at random. First your friend needs to do the diagnostics to find out the correct wire to replace… and it just might turn out to be a relay, a fuse, or some other cause. Otherwise he cold easily be changing wires forever and never fix the car.

Make sure the alternator ground makes a solid connection to the chassis. Likewise the battery ground. It should be less than 0.005 ohms.

Thank you the same mountainbike, he has diagnostic device that gives all the error codes and still can’t tell. He is a very much a GUY so for whatever reason, he won’t come here and ask. It’s me who is asking and I’m probably making him sound like he knows less than he does, because I am relaying second hand and I don’t understand it. But he has checked the things mentioned here already… and says this is very unusual to have all these things check out and it still won’t work. I just thought I’d come on here and see if anyone has another idea. Something less obvious that the battery (brand new and it’s the second brand new one, but they keep draining, which is why he replaced the alternator), the alternator (brand new) or the connections between the two… ?

This could be a grounding issue. The negative battery cable has to ground to both the engine and the frame of the car. The frame and the engine must also be bonded together with a wire or series of wires between the frame and the engine. If the engine and the frame are not at the same ground potential, it will make the dash lights and the headlights flash. It can also damage the electronics in the car.

Sometimes you just need a real mechanic.

oldtimer, ideally, yes, but she doesn’t have a dime to her name, and we already helped out with parts, that’s the best we can do :frowning:

Working on this issue without proper test equipment (a voltmeter) is about like trying to shoot at a target 200 yards away, in total darkness. If your BF doesn’t have one he should think about purchasing one. A low cost one is about 25 dollars and can be one of the best tools you ever own if you know how to use it properly.

The diagnostic device he has that gives the error codes won’t help for this problem.
He’s going to need, and know how to use, a multimeter, a schematic, a wiring diagram, and perhaps a battery tester.

The code reader he has only reads error codes stored in the engine’s computer. Those codes only store if the car’s sensors detect an error on something that may cause excessive emissions if not corrected and errors in mandated safety systems. Contrary to the belief of the general public, they do not and are not designed to monitor all the operations of the car’s systems. And they’re definitely not designed to detect electrical problems unless they fit one of the above categories.

There is one outside possibility to trouble shoot this. It sounds like you may have what’s called a “parasitic drain”, something drawing juice from the battery while the car sits. Try removing all the unnecessary fuses (for accessory systems) and see if the drain stops. If it does, replace them one by one. When a specific fuse replacement causes the drain to return, you’ll know which circuit is the problem.

Schematics and wiring diagrams can be obtained free of charge at the dealer’s parts counter once you know what circuit you need. From there, your BF can look for a possible short to ground, perhaps due to a chafed insulation spot. It’ll probably be somewhere where the wiring harness (bundle) passes through a body cavity, like from the body to the door.


Parasitic drain . . . yet another reason why BF should buy a multimeter

I have an '88 Supra that recently had a charging problem. The alternator bench-tested fine, so I did a voltage drop test between the alternator and battery. I found a full volt drop between the positives and a .22 volt drop across the negatives. I wound up rewiring the positive lead and got the total voltage drop to .32v, eliminating my charging problem. Go to Youtube and search for ‘voltage drop test’ to see how to do it. There are a couple that use a carbon pile, but if you turn on all electrical items, including the headlights, it will serve the same function.

the same mountainbike, and others willing to help… thank you. What is the difference between a $7.88 multimeter and a $130 one? Or more to the point, will a $7.88 one from Amazon, with 4.5 stars from reviews, be likely to help? When I look up “schematic,” I see battery chargers? We have one but I’ve never heard it referred to that way (Again, I’m the one here asking, and I’m clueless… it’s just that I already asked my BF to fix my friend’s car and don’t want to make him do even more work, so I’m trying…) Got wiring diagrams online. We have access to a battery tester… as I said, batteries keep getting drained.

I’m wondering about the mention of a grounding problem. When we undid the jumper cables… detached from the helper car, then removed negative from the positive car … Saturn still running. But when we detach the negative (even though cables are not attached to any other car, remember), the car dies…