insame1

I recently changed my water pump and then instantly got a battery/alternator warring on the dash. Today I changed the alternator and got the same error/symptoms. I charged the battery overnight. It was at 12.3v when I installed it. I checked the voltage in the dash at it was at 11.6v and very slowly dropping. Any help would be great this is my DD

Lenin

Is the voltage dropping overnight without you running the car? Or is the voltage dropping while you are running the car? Or both?

insame1

it holds steady until the car is running. I suspect I messed up a ground at the battery or the alternator.

I think this car is going to have to get put on the back burner for now and Ill fix up my b2000 and DD it for a while. I cant afford to keep fixing this thing. As a mater of fact I would take an 5k loss and sell it for 10k right now if I could.

Lenin

Never say die...

if you need any info out of MB WIS manual, let me know. I have full access.

insame1

Is there a diagram of the charging system?

Lenin

Is this what you are looking for?

C230 Mulac

Double check the connections at the alternator. You must have disconnected or not reconnected something properly. That's the only thing I could think of that would affect the battery voltage dropping.

Process of elimination...
Alternator is new...
Battery is how old? Although if it's holding its charge it should be okay
Check connections...

insame1

Thanks but not exactly. I dont know where the ground cables run to and was hoping to find something that would show where they go?

insame1

update.

the new alternator is making noise now. i found the the harnessed plug was not attached. I plugged it in hopeful that it would resolve the problem but, it didn't.

Lenin

Not sure which ground cables you are referring to. There is one ground cable that connects the battery to the body.

insame1

I'm going to rewire the alternator. Does anyone have a diagram of how the wires are run to/form the alternator/battery?

insame1

I swapped in a know (3rd) alternator and it started charging. I still had the warning on the dash but that could have been from the battery only being at 11.5v

insame1

So got that alternator rebuilt and installed and now it is not charging. I think it may have something to do with the battery light wire. It had a small section of the wire exposed. I was rebuilding everything when I lost the nut on the back of the PSK and it was 10:30 so no place was open to get another. I went on my lunch and will try it out tonight.

Does anyone know where the solid blue wire goes. I think I found it but I am not sure.

If I cant get this car going by Friday I will be calling it and getting something more piratical (like a matrix ewe) I have kept the little lady happy with my bad purchase until now but the $500 and counting rental call bill is not helping my case.

Any help would be great. If not it will be for sale Monday.

Supgee

I had many issues with my C32 charging/starting.. and alternator battery warnings.

Check my thread out, it may be helpful.
https://mbworld.org/forums/c32-amg-c...lternator.html

What I ultimately ended up finding out, after replacing my alternator 3 times.. is that.. both the battery and alternator were bad... causing an issue with eachother. I know it hasn't been mentioned... but how old is your battery? What is the rated cranking amps compared to actual? (get it tested) Consider replacement.
My oem alternator bit the dust (very obviously bad, seized.. could not rotate it by hand). So I said okay, and replaced it with a quality rebuild. (did not change battery) I charged the battery fully, everything was ok... replaced the alternator.. I was fine for about 2 months.. then the same issues started happening.. no alternator charge... so I said fine, maybe this one is bad too. I ended up replacing it again, with a factory OEM alternator and had the same issue.. would not charge. The sr. tech at the dealership I work for (I work for Mercedes Benz Canada) had a look at it, and could not find fault. Sometimes it would charge, other times not. Either way, red light on always. Couldn't find issue with any ground connections anyway, no problems with either of the SAM control units.. I was kind of stumped.. so.. long story short I replaced the battery with a brand new OEM battery from the dealership... my (3rd) alternator started charging again... and its been about a year since with no issues....

Just my 0.02!

insame1

I replaced the battery with a new MB battery from the dealer with no change. I am hopeful going to get a used plug that attaches to the alternator today.

Saturday I made a very tough decision and bought my wife a 13 Kia Rio. That means the c32 is going to be for sale as so as it runs correctly.

insame1

Does anyone know if we have this part a203545803 in the 02-04 203. This is supposed to be a battery terminal fuse box. I have heard of there being large fuses in these cars. all of the ones I have found have been 50 or less. I didi find this chart but there is no way for me to link it to the pre 05 w203 http://benzbits.com/w203/PreFuse.pdf

insame1

well..... Put in new SAM and it charged for 3 trips then Boom. nothing again.

southernwake

Alright well battery and alternator have been replaced and all wires appear to be connected and in good shape. Correct?

Is the battery draining overnight? or over the course of a couple days?

Taking a page out of my personal experience with my 2002 C32.. Purchased the car and had it for a few months and then the car was dead one day when I went to start it. Charged it up and it was fine. Died again the next day, after sitting for 8+ hours. Charged it up again and then had the battery checked, it was fine. Started to do some research and discovered that the control modules for the seats were known for causing drains on the battery. They fail and keep the car's system running instead of it shutting off after a few minutes after the car has been turned off.
So my question to you is, have the modules been replaced or are they still the OEM units? Have they been "bypassed"? There is a writeup on how to bypass them ( reman ones are around $250+ each) and retain the use of your seat controls but you lose the memory function. Heck of a lot less headache than a dead car.

I know it may seem like a long shot since you werent anywhere near them when the issue started, but sometimes weird crap happens. I would charge it and unplug the seat modules and see if the battery dies and at least rule them out if I were in your place.

Andrew

Andrew

insame1

thanks for the info but unfortunately/fortunately the battery does not loose charge unless the car is on because the battery is not being charge by the alternator.

insame1

Just to Finnish this thread up. After over 2 months and $1000 it was one wire broken inside the insulation running from the alt to the sam unit.

cm60k

Thankss for sharing that, definitely will help a looooooot..

ZAYED,,