I have a 2000 S430. she's beautiful... a week or two ago i noticed my battery was low. i charged it, and still after a day or two, it was dead. I had a buddy test the alt, and it was only putting out 11v, and that's AT the alternator... had it rebuilt... reinstalled... tested it, and it puts out 14v now... i drove it off my lot, made it 3 blocks, and the low battery indicator came on. then she shut off.

Before i had the alternator rebuilt, the car would still run even with the battery disconnected, even though only 11v were being put out.

Now, the car won't even run without a battery connected, but it only runs, it doesn't charge it...

any ideas?




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Shouldn't run an alternator without a load (i.e. battery) connected.

Alternator output of 14v is in the correct ball park but this is what should be seen at the battery terminals with the engine running.

Battery voltage with the engine off must be above 12.5v otherwise the battery is scrap.
A recharge does not offset PERMANENT damage that will have occurred to the battery if its voltage has gone below 12.5.

Stuart

 

yup i'm losing the voltage somewhere between the alternator & the battery terminals... is there any fuse i might be overlooking?

 

there is a prefuse block under the passenger side carpet toward the front under the dash. its a large block with fuses that are not supposed to be replaced and 2 large power wires running to it. if you shorted anything out or sparked a wire while changing the alternator you could have blown this fuse block. its attached to the floor board under carpet and some other paneling

 

If you measure the volts at the battery with the engine OFF and then ON you will be able to determine if this fuse has blown.

If the fuse has blown you will not have power from the battery to crank the engine and likewise the output from the alternator will not get to the battery to recharge it.

Measure the volts at the battery.

12.5+ with engine OFF. About 14.5 with engine running at about 1500 revs.

Stuart

 

Oops.

Didn't see Chassis221 reply.

Question is whether you don't have output on the alternator or the lead to the battery is fused, broken / poor connection..
Its a 80amp type fuse and doesn't blow easily. Must have been a big short (spark) to blow it!

 

awesome... i knew about that panel down there but didn't know there were fuses under the black plastic box... i'm gonna check that and hopefully it solves my problem. thanks very much i really appreciate this...

oh... is the fuse easily attainable? or is it some special order type of fuse? lol

 

supposed to buy a whole new block. the fuses are not available threw benz.....maybe someother place..

 

well... guess i'm about to find out tomorrow... lol... thanks you all have helped me so much you don't even know...

 

hi xninjax wat kinda headlights are those and werd ugetm if u dnt mind?