1995 C280 Electrical Problems
 

This is going to be a little lengthy... so here goes.

For the past few months, my mechanic has been telling me my battery is weak, but I had no symptoms, and a relatively new MB battery, so I brushed it off.
Starting 3 or 4 days ago, I would randomly notice my battery light (in the instrument cluster) was dimly lit... on and off... and as it got worse, the ABS light came on as well. Well finally last night, I was driving along, and noticed my headlights dimming.. then my radio turned off, then the power windows slowed, and the car died. If I waited about 5 min, it would barely restart, then shut off.
So I had MB RoadSide Assistance give me a new battery last night. Car has driven just fine since... however, the battery light is still dimly lit. My alternator is going south right?
Could this also be the reason my SRS code won't clear (dealer says it won't clear, so I need a new SRS module?).

I'm taking the car in Sun when I go out of town, so we'll see what happens... I just wanted a little heads up... I think alternator.

Thanks everyone!

It sounds like you have all the classic symptoms of a bad alternator.

Bad alternator most likely, measure the voltage in the system with the alternator running to see if it is running at battery voltage or the correct voltage.

Well, after about 24 hours, and 30 miles later... the battery died again. Battery light brightened, ABS light came on, lights dim, and car died. AAA charged up my battery real good, and then followed me home. I made it just fine. Yup, sounds like the alternator to me too.
I've got it hooked up to a wall charger, on SLOW charge all night to be sure I can get to work in the morning (530 AM!!).
I'm taking it in Sunday.

Thanks. :)

BTW, anyone know how much an alternator is for my car?

Here is a quote from Fast Lane:

F4000-51631 Alternator Bosch

List Price $291.00
Sale Price $185.91

Core charge $75.00

Changing Alternator
 

I'll walk you through the steps on how to change the alternator. It can be tricky especially when you have to loosen the belt. Drop me a line if you have any questions. I just replaced my alternator and all is well.

Well here's an update. I took my car to my mech... they couldn't find anything wrong with the car. THey said the alternator is doing it's job, but that the belt is not pulling the alternator properly. From eyesight, the belt is spinning everything just fine. My car is still not fixed. before the end of today, I"m taknig it to the Mercedes dealership and getting a RENTAL!

I'll keep you posted.

Alternator
 

David,

I suspect that your alternator is going bad. If the pulley is not pulling I mean let's think about this logically. If the belt is tight and it's turning, then it should turn the alternator. If your battery is not charging then it's your alternator.

Before spending a bunch of money at a dealer I would buy a new alternator, install it then see for yourself. If, in fact, it's not the alternator return it.

Jonathan

Hi,

I guess it all depends on where you buy the alternator.

If the belt tensioner fails and the belt loosenes, the alternator might not spin at full speed. The belt tensioner is a rubber bushing that tensions the belt as the bushing is twisted by the adjustment screw.

Some mechanic I have? Mercedes-Benz says the alternator is shot.... I just ordered a new one via PartsShop. Thanks for the Part # Paul. I'll have the new one put in, hopefully by me, tomorrow. I shoulda known it was just the alternator!

Anyways, I'll keep you posted.
Thanks for all the tips guys. ;)

are you sure it is the alternator not the brushes and the voltage regulator?

At this point? I sure hope not...............

I second that. It's usually a good gamble to try an unreturnable $40 regulator before getting a new alternator (which comes with a new regulator).

David, I'm surprised you didn't pick this up in the archives. Classic worn regulator brushes symptoms.

Sixto
91 300SE
87 300SDL
83 300SD

Reburbished Alternator
 

Hi guys,

I just replaced my alternator with a refurbished one from Partshop.com with Phil. I had to return the old one (core). The refurbished one is working great.

Jonathan