By November 7, 2012 2 Comments Read More →

Dim Headlights Troubleshooting

I have a question about my Chevy S10. The lights and anything electrical continuously flicker. The voltage meter does the same thing. When it started out I could barely notice but it has started to get worse(lights continuously get very bright then very dim).

I thought it must be the alternator but the truck has never died nor the battery gone dead. Any suggestions?


Howdy Shawn,


It is most likely a problem with the voltage regulator inside the alternator. The alternator can still be producing electricity to keep the battery charged, but the part inside the alternator that regulates how much electricity to send to the battery probably has a problem.

You can get a starter/alternator repair shop to just replace the regulator…..but if it was me, I would just replace the whole alternator. If one part of the alternator is worn out, chances are more parts are worn out as well.

An alternator shop should have a few of these alternators sitting on their selves to install for you……of course, get them to test YOUR old alternator on the vehicle and concur that the regulator is the problem BEFORE you remove it.



Austin Davis

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Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."
  • Austin Davis

    Yes it could be a loose ground wire connection or just a bad light connection, so check the wires to make sure they are tight and in good condition. I would probably first try a new bulb, or swap the passenger bulb to the driver side and see if the bulb is the culprit.

  • glen

    2003 toyota camry. passenger side headlight fluctuates between brite and dim. Driver side is normal.
    Could it be a ground wire. Alternator was replaced one week ago.
    Thanks in advance for any solutions.