alternator/charging problem
Thread Starter
Junior Member
Joined: Oct 2015
Posts: 19
Likes: 1
1997 mercedes e 300d
alternator/charging problem
recently, my 97 e300d started shaking alot and I noticed it does it when its cold out. I took a look on the aac and it showed my voltage was not consistent and it would drop to 12.4 volts on occasion but then the alternator would kick back in a charge for a second and then repeat the cycle. Confused, I took a look at the alternator to find the original positive wire dangling freely, with a broken ring terminal. luckily I ran a second power cable to battery previously (for my audio system) so it still had power going to the battery. i ended up buying a new ring terminal and crimping it back on.
I thought that would solve the problem but now the alternator does not charge the battery at all. I have a 250 amp alt in there and i have the original one as well. I tried swapping them out, with no luck and i went to test the high output alternator at a local shop and it was fine. I also replaced the belt with no luck.
I checked all the fuses, and the exciter wire for the alternator and they are all good. the strange part is after i drive the car for 10 min, the voltage abruptly goes up to 11.5 on the aac and stays there. also when I start the car, i get abs and ets warning messages.
I literally have no idea what it could be. I have 2 batteries and they both tested fine. one thing I have noticed is I used to get a bad light bulb message every time i started the car(i broke the daytime running light terminal and currently no bulb in there) but after these issues, i get warning message for everything but that.
I thought that would solve the problem but now the alternator does not charge the battery at all. I have a 250 amp alt in there and i have the original one as well. I tried swapping them out, with no luck and i went to test the high output alternator at a local shop and it was fine. I also replaced the belt with no luck.
I checked all the fuses, and the exciter wire for the alternator and they are all good. the strange part is after i drive the car for 10 min, the voltage abruptly goes up to 11.5 on the aac and stays there. also when I start the car, i get abs and ets warning messages.
I literally have no idea what it could be. I have 2 batteries and they both tested fine. one thing I have noticed is I used to get a bad light bulb message every time i started the car(i broke the daytime running light terminal and currently no bulb in there) but after these issues, i get warning message for everything but that.
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Joined: Nov 2012
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A gaggle of MB's
You might see if some of the Diesel boys weight in about checking your belt tensioner/spring-shock - sometimes belt slippage can lead to "charging problems"...
More experienced members should be checking in on this thread with a bit of patience.
More experienced members should be checking in on this thread with a bit of patience.
Thread Starter
Junior Member
Joined: Oct 2015
Posts: 19
Likes: 1
1997 mercedes e 300d
well I installed the high output alternator back in and it is charging the battery. it still "turned off" for about 30 seconds on my test ride but then the voltage went back up again. Im gonna give the company I bought the alternator from a call and hopefully they will send me a new one. it should be covered with the warranty
