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Battery voltage high

1995 Cadillac DeVille 4.9 L

Check engine soon light comes on, battery voltage high. When I increase speed the head lamps get brighter when I decrease speed the head lamps get dimmer. I changed the alternator because thats what a mechanic said I needed but I still have the problen battery voltage high.

Will this damage the battery or other components? Should I stop driving the car.

I suggest having someone test both the battery and the alternator. Most auto parts stores will do this free.

Did anyone test your alternator before you replaced it?

The battery is new and so is the alternator.

You have shorted voltage regulator. (It’s located inside the alternator). Don’t drive too much or you will cook the battery.

Besides a check engine light saying “battery voltage high” have you measured just what voltage is present at the battery, how high?

To prevent any damage due to the high voltage you can disable the alternator by disconnecting the plug in the rear of it. You will then be running on just the battery so you will need to keep any extra accessories off that you don’t need and drive it to a nearby shop to have the trouble fixed.