I have C200 - w203 and the car is in good shape so far. I have recently bought it and someone told me to check the regulator voltage at load. I connected the voltmeter at load and the voltage shown at the battery terminals was 13.1 volts. I read it should be close to 14 volts to charge the battery well and keep the remaining electronics in order. Does anyone know if it makes sense? Having some electrical background, I know that even 13.1 is good enough to charge the battery but would take longer since these cars are not equipped with smart chargers. The darlington, T-type three pin modules should not deteriorate with time and it could only be carbon brushes attached to the alternator. Should I take out and replace the carbon brushes after cleaning the commutator on the alternator or replace the whole thing or leave it as it is. Kindly advise

 

If it is indeed your voltage regulator & not your alternator, It'd be smart to change the whole regulator. Also, our cars are equipped with a voltage meter in the cluster. Turn your car key into position one (mileage must be showing) & press the trip reset button 3 times.

 

Thankyou but pressing the button three times did not change the display. Please also reconfirm that is it right that voltage at the battery terminal should be 14 volts when the engine is running?

 

Was your mileage displaying? & what year? Here's the video:
But on my 2003 C240 4MATIC, When I first turn it on it's anywhere from 13.7 - 14.2 volts. If your battery isn't dying out (I'd also check to see if your battery is good) & your electronics aren't doing anything weird, I'd say you could leave it alone for awhile. But if you have the spare $$$, I'd replace the regulator.

 

I was a bit concerned because someone told me that if the voltage is not as per required level, the controls go balogne and one could have weird things happening like unsmooth shift of gears - this is an automatic transmission. so I was thinking to check it. My friend got similar regulator from ebay for 30 dollars.

 

The worse thing I can see happening with an under voltage is your car dying out completely. & That's only if your voltage keeps dropping. My car used to go to around 13.0v while driving. I had a faulty spark plug wire & it caused all my electronics to pulse. I also had a very rough idle. But if it's steady at around 13v, you should be ok temporarily.

 

Thanks for your prompt responses. Well I just rechecked it and it displayed. it was 13.6 volts and when I cranked it and took it to 2000 rpm with lights and AC on, the voltage went to 14.2 volts. so I reckon it should be ok is it?

 

Definitely, you're good to go lol. That is factory specs, seems like everything is normal.

 

Hey! Thanks. What is the difference between c200 and c230? Aren't they both w203 generation and more or less similar cars?

 

They're similar, but I believe the c200 only has 160hp & the c230 has like 190hp. Assuming you have the kompressor.