sirterrytibbs

Hi, My 2002 clk 230 has had loads of problems with the alternator. I have had it replaced once and had a second refurb just in case but I keep getting this overcharging warning on the dash and it pop's my lights. It will be fine for a few days then goes starts again and goes into limp mode. Please help im going mad. Thanks

miatawnt2b

did you replace the voltage regulator?

sirterrytibbs

Yes it was the first thing I did, its had 3 different one's since. Could it be the battery although that's only a few months old.

sirterrytibbs

Does anyone have any ideas on what could be wrong? What can make my electrics mess up like this?

miatawnt2b

any codes? My guess is alternator/regulator/battery/ECU, but I don't have much diagnostic to go on. I also don't know exactly how the w208 regulates charging. It's old enough I can't imagine that it's an overly complex charging system. If you put a volt meter on the battery, what is the voltage when the car is off, on and cranking? Maybe go to a local parts store and have the battery tested.

sirterrytibbs

Thanks for responding. I'm having the diagnostics done tomorrow as I can't drive it so don't have any codes yet. From what I can work out is itddoesn't know when to turn off charging, it boiled my battery there is so much going through it. I have a basic teater that said with car off its on 13.6v and 15+ running.

sirterrytibbs

Does anyone know if there should be 2 or 3 cables connected to the alternator?

miatawnt2b

15+ is definitely too high. should be 14.8 or so.

miatawnt2b

without looking at it, this is how they are usually set up. There should be a plug connection going to the back of the alternator into the regulator. Then there will be a positive lead that is a screw lug terminal that is pretty thick guage wire. Then some cars have a negative thick cable on a screw lug connector as well, but others don't.

sirterrytibbs

There isn't a plug just two terminals. There is a skinny cable a fat one to the battery. There is another cable that's loose and not sure if it connects or not but I think that goes to the starter motor. And not sure if it should or not connect.

miatawnt2b

http://www.ebay.co.uk/itm/MERCEDES-C...-/121294041742

from this pic looks like 2 wires... a thick single wire lug and a connector into the regulator.

miatawnt2b

is it possible the old alternator or regulator fried the battery and you're really seeing a symptom of a cooked battery? Was the new alternator/regulator new off the shelf unit or used?

sirterrytibbs

http://m.ebay.co.uk/itm/360764396317?nav=SEARCH

Thanks for response. The link is the one I have fitted, it is a reconditioned one but ive taken it back 4 times and the only thing that's not new is the case, including 3 regulators.

sirterrytibbs

Ive had diagnostics done but only showed up as voltage problem but that's about it and expected that really. One thing I just noticed taking it off was the thin wire on the back was loose, does anyone know what this does and would it make the alt work harder than normal as its pushing 19v