W140 Battery Light
 

I have a 1997 S500 with 45,000 miles on it. Today the battery light came on - no other symptoms or problems. The light stayed on, but dimmed every now and then. I parked the car and opened hood - nothing looked wet or out of sorts. Got back in car and the fuel gage warning lights were blinking in addition to the battery light.
All the interior lights are bright and look good.
Thoughts?

Battery Voltage?
 

What is your battery voltage? Take both readings while the engine is running and then with it off (with no lights or accessories on). A simple voltmeter will tell you what you need to know. A fully charged battery should be 12.65 VDC static and around 14.2 VDC running. Lights can look bright even at 12 volts, but at that voltage the battery is only half charged. The light on could mean the alternator has crapped out, internally. A voltage check may or may not reveal the problem, but it's a good place to start.

Michael B.

Dont forget to check your voltage regulator.