Car stalls, gauges, radio and lights go out while driving

Tiny
SICKPETE
  • MEMBER
  • 2003 HYUNDAI SONATA
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 192,000 MILES
I have already replaced the battery, the negative battery cable, and the alternator. Battery light doesn't come on but after driving the speedometer and the gauges stop working. The radio will cut out and if I stop and turn off the car it won't restart. I had to reconnect the alternator and got it bench tested because the voltage regulator wasn't showing anything. The alternator tested good and after I put it back in, I was told that everything was working, and the battery is still good. I don't know if I may have a fuse problem or if I got lied to by AutoZone but the car will run after I recharge the battery and then a day later the electrical problems start updating but no battery light comes on. Any ideas?
Thursday, February 24th, 2022 AT 11:55 AM

6 Replies

Tiny
SICKPETE
  • MEMBER
  • 5 POSTS
Ment to say "start up again" not updating.
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Thursday, February 24th, 2022 AT 2:11 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

Based on your description, it sounds like the alternator isn't keeping up with the demand. I need you to check something for me. We need to confirm the alternator is performing at a rate that will keep things alive.

It's really simple to test. All you need is a voltmeter or a multimeter. Follow the directions in this link.

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Let me know the results. I would like to start with this before we try finding a poor connection (which I don't feel is).

If the alternator fails the test above, I need you to check two more things. First, in the under-hood fuse box, there is a 10-amp ECM fuse. Confirm it is good and has power to and from it.

If that checks good, I need you to locate the white wire on the alternator. That wire which sends a charge to the battery has a fusible link. A fusible link is similar to a fuse but can look like a wire. So, what you will need to do is disconnect the negative battery terminal. Then, check the white wire for continuity to the positive battery terminal. If there is no continuity, it is likely the link has failed.

Here is a link that explains how to test wiring.

https://www.2carpros.com/articles/how-to-check-wiring

Take care and I'll watch for your reply.

Joe

Note: I attached the wiring schematic below of the circuit. I had to cut it in half to make it readable for you. I thought this may be helpful for you. Also, the last pic shows the fuse I'm referring to in the fuse box. It's fuse 26
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Thursday, February 24th, 2022 AT 7:50 PM
Tiny
SICKPETE
  • MEMBER
  • 5 POSTS
Hey thanks for the reply. Sorry it took me awhile to get back. I tested the battery and the alternator. The battery stayed the same when I had the car running. I tested the ECM fuse, and it was good. When I went to test the fusible link, I disconnected the connection from the alternator I didn't get a reading on the voltmeter when I disconnected the negative battery cable but when I connected the negative battery cable the connection got a reading of what the battery level was at. I don't know if that's good or bad but nothing happened when it was just the positive side. Again, I don't know if I did it right though. There is a 120 a fuse on the positive connection size but it's a pain to get it out.
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Saturday, February 26th, 2022 AT 12:50 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

When you disconnected the battery and the fusible link, there wouldn't have been any power. If you did get power when you reconnected it, the fusible link is good.

The fusible link is the 120-amp fuse, so it appears good.

When you checked alternator output at the battery, you indicated there was no change in voltage between the engine being off and running. If everything electrical is good, the alternator isn't producing. You may have gotten a bad one.

One last thing. I need you to connect your voltmeter to the S terminal (orange wire) at the alternator (with the battery connected). Place the red connector to terminal S and the black wire on the meter to the battery ground. Note, you can disconnect the connector at the alternator to do this. Also, one more time, confirm there is power (battery connected) to the B terminal (white wire) at the alternator using the same technique.

If they both have power, replace the alternator.

Let me know what you find or if you have questions.

Take care,

Joe
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Saturday, February 26th, 2022 AT 7:43 PM
Tiny
SICKPETE
  • MEMBER
  • 5 POSTS
I ended up having to get a new alternator. Everything else checked out when I tested it. Now with the new alternator it seems to be charging the battery my battery was at 11 but when I ran the car with the new alternator it was jumping up to almost 13 so I probably just need to run it to see if the battery will charge all the way. Thank you for all your help and advice. If I notice anything weird I will probably reply again.
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Sunday, February 27th, 2022 AT 3:39 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

First, you are very welcome. I had a feeling that was the issue, but they told you the alternator was good. Hopefully, they just tested it wrong.

The battery, even fully charged, won't produce 13v. This indicates the alternator is doing its job.

Drive it for a few days and then recheck it. I suspect you will find when running, it will be around 14v and 12v with everything turned off. If that doesn't happen, let me know.

If things change, let me know. Also, please feel free to come back anytime in the future. You are always welcome here.

Take care,

Joe
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Sunday, February 27th, 2022 AT 7:54 PM

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