I had noticed the battery light coming on at night, and early in the morning with my lights on. The light would go off, and I had no trouble starting, until this weekend after taking my wife and daughter out for dinner and a movie my car wouldn't start.

The next morning I pulled the old battery and had it tested. My battery was less than one year old, but tested bad. Replaced battery. Also, after reading several posts about changing out the voltage regulator, I pulled the voltage regulator (internal Bosch). The old voltage regulator brushes were wore down to nubs, so I replaced it with a new one.

With the new battery and new VR, I started it up, battery light came on at first, but then went out. I then drove around for about 10 miles with all lights on, AC running, windows rolled up and down etc. Battery light never came on, starts great.

This morning when driving in the battery light comes on again . As before, the light is intermittent. On the way back home this evening the battery light doesn't come on. I take it to the parts store where I bought the battery and they tell me that the charging system is not charging.

Do I need a new alternator, or did I somehow screw up installing the VR?

Thanks in advance.

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1989 300E
103,500 miles

1982 300SD
Sold but not forgotten