Hi All,

New to forum...been lurking since I got my 1982 300SD a few months ago. Great forum, very helpful, thanks all! This is my first MB and my first diesel, but I am learning a great deal here!

I am experiencing battery drain/non-charging. The battery light has been coming on intermittently since I got the car.

Long story below, followed by what I've done (if you just want to skip to #1 below)

I was told by PO it had a brand new battery. No corrosion on terminals. When the problem was first experienced, I removed the alternator and had it bench tested at the local parts store. Checked out OK. Upon re-installation, the problem went away for a while...then, it came back. Once again going on and off at different times. My girlfriend is the primary driver of the car, so I am not sure how long it had been happening. I did notice it seemed like the light would flash when going over RR tracks, etc. We then began to experience a no crank situation (the car would eventually start after 2-3 no cranks). Upon a closer inspection of the alternator, I noticed the plastic mounting clip on the voltage regulator was cracked on one side. I figured this may be the cause of the non charging and the flashing of the battery light, so I changed the VR (I also cleaned the alternator harness at that time). I charged the battery and everything was great...for a few weeks. Most recently, the battery light would glow dimly on upon start up and occasionally shine bright all during the same trip. We ended up getting stuck at with a dead battery at Circle K.

To the best of my recollection, here is what I have done:

1. Changed voltage regulator

2. Had alternator bench tested twice (both check OK)

3. Had battery tested out of car (check OK)

4. Had charging system test at local auto parts store with the little hand held unit they use (battery check OK, alternator test bad at only 12.06V - although the car was not really warmed up and the guy was kind of in a hurry)

5. Did the ground terminal/ammeter test for drain with engine off: 10mA (approx, using cheap multimeter) which I assume is the clock. Also did the test light/ground terminal check and couldn't see any noticeable drain.

6. Cleaned engine ground to body contact(the twisted cable). Was unable to remove contact from motor for cleaning because it needed a special wrench.

6 1/2. Checked belt deflection (approx. 1/2" w/ thumb pressure) and visual inspection of belts (1035mm belts look almost new)

7. Most recent voltage tests (after 2nd removal of alternator for bench testing and full battery charge):

Across battery, engine on at idle: 12.4 (No increase at approx 3000RPM)

Across battery, engine off:12.55

Also performed alternator harness test from post #3, got battery voltage at both red wires (with neg. lead on voltmeter ground to body and pos. to one wire at a time). Did not however perform test on blue wire yet.

I took it on a ten minute test drive and was still getting a dimly lit battery light.

Battery light is off when ignition off, comes on when ignition on, stays on when running, will vary from dim to bright. Had occasion periods during trouble shooting when battery light would stay off when engine running and everything would appear to be normal.

Please advise if this post is too long or confusing, this is my attempt at being thorough.

Any suggestions welcome! Thanks! Also, I will be away from internet for about a week coming up. Please forgive any delayed replies to any posts.