Do I nee3d to replace the alternatoron my S430 Mercedes 2002 Model. My mechanic sasys it is responsible for causing battery drain overnight. Car will never start in morning as battery is dead.

Dean Joly

• 788 Answers
• Posted on Jun 09, 2008

SOURCE: Car Battery draining over night

Something is shorted and it could be very difficult to find sometimes. It could be something as simple as a button being pressed when it shouldn't turning on a light or feature that runs all the time, but in a 2001 that is unlikely as it should turn off all lights after a certain period of time. It could be something in the radio. What I suggest is to pull one fuse at a time for accessories, check your manual for what each fuse powers. If the battery still drains with that fuse out then put it back in a pull another. When you find the fuse that allows your battery to keep it's charge then you will have a much smaller field of offending components.

For example, if you pull the fuse that powers the radio and heater, and the battery keeps it's charge then you know it is either the heater or radio causing your problem.

This can take a few weeks to do completly but won't cost you a penny to do.

SOURCE: 2002 s430 mercedes benz alarm keeps going off

change the batteries in the car alarm remote if you can.

gord storey

• 477 Answers
• Posted on Jun 04, 2009

SOURCE: MY WILL NOT START THE CAR C240 MERCEDES BATTERY IS NOT DEAD

I am assuming that the engine won't even turn over. could be lots of different things. The simplist is to make sure the car in in PARK , won't start if not. Other things could be , Security imobilizer if you have one. Does your key have a electronic chip in it ? Try your other set of keys if you have one. Check if battery connections are clean and tight.

SOURCE: battery on mercedes A140 drains. I drove the car

aftermarket stereo? dome lights? car alarm? Use a multimeter and see what fuse has power draw when car is off.

SOURCE: battery is going dead

check ur alternator