Battery/alternator warning light

[Dallas]

I have a 2001 C200K. The red warning light has come on re battery/alternator problems. My MB dealer says the battery and alternator test OK and the car still drives OK. Every morning the light has gone out and it then comes on again anywhere between 2 and 50 miles later. Dealer now wants to fit new alternator "just in case" Any ideas?

 

[LANDR0VER]

Have someone put a meter on the battery and check if it is charging ok.It should read13.5volts or higher.

 

[OlafMaxwell]

Friend of mine had that problem.

Dealer insisted alternator, friend insisted battery.

Dealer fitted alternator, assured friend he had the alternator tested and that it was faulty, bill for about ?700!!

Problem still there......

This time dealer fits battery, problem cured.....

Friend asks for and gets alternator back......gets it tested.....tester reports....alternator perfect, also reports it was never tested!!! Friend goes back to MB dealer, demands they refit the old alternator and a refund of his money. Dealer says can't do that...lawyer gets involved, MB dealer takes car back and refits old alternator and refunds money!!

Friend cancels new Merc and orders Jaguar instead.

Your car is 2001, battery life is variable but 4 years I would be expecting a battery problem. Those lights come on when battery is dodgy.

 

[jberks]

To be fair, it could be either. In the old days, the alternator drove the light (not sure with a newish merc) and a faulty alternator regulator could cause the symptoms you describe. A battery can last from 3 -15 years so its impossible to say which. Bob it into one of the battery/exhaust places who will do a free check, but it may be an intermittent alternator fault or even just a duff connection, in which case it will check out ok.
I had the Mother in laws 2000 megane checked recently as it wouldnt turn over. Got it going, took it to a garage. They checked the system - all fine. Tried to restart the car - chug - nothing - battery dead. Can be a bugger to pinpoint.
If in doubt the battery is a far cheaper option to start with. Also, I'd never pay dealer prices for an alternator. There are lots of good recon people in every town and they can even do your own. Often its just a case of replacing the regulator module and brushes and its good for another 100k. (£30 not £500!) Had bearings replaced in one many years ago, ran the car for another 4 years and never heard from it. Alternators are easily repairable but the dealer will only replace with a very expensive new one.

 

[guydewdney]

try this test:-

turn everything on electrical - heated seats, windows, fans, lights, hazards.

does the fan belt squeel? does the alt light come on? might just be as simple as a belt slipping.. try a bit of belt grip spray (most AA people have it on the van, or a decent bearing supplier will sell it)

clean the battery terminals and the other end of the earth lead (the one to the chassis) and the chassis point / put a new bolt / nut on / in... - its free and easy to do. Once done, cover connections in grease / vasaline

 

[paulinegaye]

Alternator

I have a 2001 C200K. The red warning light has come on re battery/alternator problems. My MB dealer says the battery and alternator test OK and the car still drives OK. Every morning the light has gone out and it then comes on again anywhere between 2 and 50 miles later. Dealer now wants to fit new alternator "just in case" Any ideas?

yes i think you should get Merc to change the alternator as the same thing happened to me and the car stopped. I had to have it towed away. Merc said i needed a new alternator cost of over £400 plus labour £400 approx. And they are recalling cars due to a fault in voltage.

 

[paulinegaye]

Alternator prob

Yes get Merc to change the Alternator, as that happened to me and i felt it a coincidence that they are recalling Mercs due to an alternator fault. Especially as i had to pay.

 

[turnipsock]

Here's a wacky idea, if you want to eleminate the battery from the possible problem list, why not try a battery out of another car?

By the way, you can get special battery contact grease out of Hellfords (It's probably vasalene). I wish the previous owner had used this as I had to get a puller onto the battery terminal to get it off.