The last two times i have gotten in my mercedes my battery light has been illuminated, my car however has glowed and started well in this 55 degree weather. What is going on??? I am so confused .

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I like cars.

I assume the battery light is on while the engine is running. Although there’s a problem with the charging system the battery is charged enough to start your car a few more times.

The group 49 batteries hold alot of power reserve. Unless you use the headlights, these old diesels draw almost no amps druing normal operation. It's possible to go for a few days with a dead alternator before any starting issues begin to show.

That's why they can get away with such weak output alternators. In contrast, the 99 F-450's I work with put out a constant 45-70amps at all times. I've even had a few stall from low voltage because of a bad alternator.

No the light was on BEFORE i put the key in it and BEFORE i started, sorry this was unclear.

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I like cars.

Odd. My car will have the alternator light on whenever I leave the engine running without the key in the switch. Soon as I stop the engine, the light goes out.

Maybe your battery is overcharged?

Some other post mentioned a shady ground, maybe I will check this out tomarrow. Thanks.

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I like cars.

Mtne stays on until i step on the pedal. Seems normal.

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'85 300D Cal 280,000 miles
'14 GLK 350 60000 miles

Had a friend with the same prob. Ill try to figure out how he fixed it