I have a C320 2001. Yesterday I came home from work a 20 min drive on the highway and just as I was pulling down the street after grabbing my mail in the pouring rain my alt/ battery light came on in red. OH GREAT! I thought, "last time I seen this message the car shut off shortly after and it just so happened to be the alternator." But this time something strange happened. A message reading " light sensor visit workshop came on" and then " BAS light" then "SRS light" "break wear light (which has been on for a yr bc I didnt get the right sensors put on so ive ignored it but breaks are fine) then windshield wipers and blinker quit working to conserve battery. So later that night I turned it on and the coolant message popped up showing it was to the halfway mark. But last time I needed coolant it actually told me add coolant so I dont think thats the prob. Today after work after the car sat all day I drove it to auto zone. Batter tested good(its 9 yrs old original battery) alt. tested good. At this point Im starting to think its neither or it wouldnt of been able to drive 3 miles w/o the car turning off as a safety b.c thats what happened 1.5 yrs ago when the alt went out. It didn't let me really get around without shutting itself off it would say car powering off (something like that) last time it went out all these other warning messages were not coming up though LAST TIME 1.5 yrs ago. I called the 2 mechanics that work on merc. and they both told me battery/alt problem. They said the other lights come on b/c its not getting enough voltage. WELL, just now i went to drive it to walmart to have them test the battery and the car would only drive 10mph b/c it would not shift gears. Ive never had a prob with the transmission and usually there are warning signs. It drove just fine to autozone 2 hours ago going 45mph. Im guessing this is a safety feature so I cant drive the car but it never died/powered off.And of course I seen the coolant message/light sensor message/srs message/ESP message/Break wear. Does anyone have a clue what this could be? FYI-its been making a weird rattle/squeak click noise sound like its a squeak coming from belts. A local mechanic replaced the belt to see if that was the problem to fix the noise rattle squeak and he told me to bring it back to him b/c the sound had not went away. Im taking it to him tomorrow so he can address the prob for free b/c I paid to have the prob alleviated and its still there. I dont know if these are realted...maybe..... probably not?!? But does anyone have any advice on what I can do? Im afraid its elect problem and gonna cost an arm and a leg at the dealership. Plus ppl try to screw young girls over...or ppl in general. Any advice is greatly appreciated!
Thanks

 

I would first change that 9 years old battery. Best way is to call MB Road Assistance 1-800-FOR-MERCedes. They will come and change your battery and you will pay just cost of battery.

 

did you ever find out what the true issue was to this problem. I have a 2002 C320 that just did the same thing, same conditions(after a heavy down pour of rain). I replaced the battery and alternator back in July so I am struggling to believe that either one is the cause.