hELLO: i HAVE A 1993 300SD. The battery light in the instrument
cluster stays on till revved up to approx 1700 RPMs when
starting the car. Once the light goes out the light stays out at any
RPM. I checked the output of the alt at idle with the light on and
there is no output. After the light is out at idle the output is
between 45 & 47 amps. At 2500 RPMs output is only 50 amps
with all accessories on.[should be near 100 amps] I pulled the
instrument cluster and checked continuity of the exciter wire
going to the alt. It was okay, and then I checked the continuity
of the wire going to the alt for continuity to ground and there was
continuity to ground with the wire was disconnected at both the alt and cluster. Is this a problem with the wiring?? Has anybody
else experienced simular problems? I have been running like this
since 1999. At that time I took it to a dealer and they worked on
it a full day, on the phone with Mercedes reps and were unable
to diagnose the problem. I never went back. Thank you anybody
and everybody.