Check "Melted fuse panel" thread just below.

I felt this new issue needed a fresh thread.

I replaced all the fuses in my fuse box. With the car off, I read 12.2v on the battery. When idle, she drops to 11.4v. When revved, the highest she'll go is 11.84v. So the alternator is charging, but not NEARLY high enough. Bad alternator? I checked the brushes about 6 months ago, and they were okay. Should I check those first?

Thanks!

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'90 300SE --- 173k miles --- (Odometer just stopped working!)

'85 Cali 300D --- 193500 miles --- (Second one) Sold Nov '10

'82 300TDT --- 236,xxx miles --- (My first one) Sold July '09

what is the volts at the battery with the key in the on position, but not running?
if it's REAL low, you may have a serious short somewhere that is too much for the alternator (it may only be 45amps)
John

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

From your numbers, the alternator is not putting out. It should be around 14v with the engine above ~2krpm provided there isn't a huge short or the battery isn't drawing a ton.

However, since the battery had higher voltage at rest than it's showing with the engine on, it appears that the alternator is not charging, at least part of the problem.

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Gone to the dark side

- Jeff