Battery Drained While Driving!
 

Hey Guys,

Just purchased a beautiful 1988 300E and 4 days later, (while driving) all the electric failed and the power drained. Ultimately the battery drained completely. I bought a brand new battery and installed it, but it drained completely overnight. Ever heard anything like this re: 300E's?

It sounds like the battery isn't being charged by the alternator, and as if there is also a short or current drain somewhere. My 87 300E drained overnight before. The alternator needed new brushes (regulator is built in the brush assembly), and the current drain turned out to be the rear seat dome light. The bulb was burned out, and I didn't see that the dash switch was in the on position. This mean t that the other 2 bulbs on that circuit in the lower rear doors were on all the time, but I never saw them. So they drained the battery overnight.