Car worked fine next day there is 3 volts in the battery couldnt even unlock it. Then i charged the car fully and now the high high beam doesnt work the turn signals goes to fast brake assistance doesnt work, redlight start stop button doesnt even light up i have checked and cleart the fault codes they come back in 2 secounds maybe 15 different codes. Today i charged the car and measured the battery was full when i was going to start it the screen sayed low battery start the engine. And it starts and drives fine. Anybody have clue what could be wrong? Is it some broken wiring?
No batterypower overnight and other problems
- Thread starter Skitbil
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It very much sounds as if battery has failed and cannot hold enough charge
How old is the battery?
How old is the battery?
The Battery is only like 11 months i tested it with some kind of device that sayed it only holds 60a but when the battery broke last time the problems was nothing like this
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If that is only holding enough charge for 60 ah (amp hours) then the battery is discharged.
I will test disconnecting the battery and charging it fully then amp test it. I just think it would be weird if the battery is broken in less than a year and the faults feel weird for a battery problem. How can the car start easily when the battery cant even run the turn signals properly. I guess i bought the cheapest battery you can find so maybe some production error, atleast it has warranty
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The battery ideally needs a load test after its been fully charged.
It's possible it has a faulty cell even though its only 11 months old.
If you are still in Sweden I'd be buying a good brand like Varta/Bosch or a Mercedes OE battery due to your extreme cold weather.
It's possible it has a faulty cell even though its only 11 months old.
If you are still in Sweden I'd be buying a good brand like Varta/Bosch or a Mercedes OE battery due to your extreme cold weather.
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The faults you describe sound exactly like those associated with a failing battery.
The multiple systems reporting errors all require a reliable and consistent power supply.
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Still under warranty?
Well im pretty sure it’s not the battery the car have been parked and locked for hours and now it have turned on highbeam lighting up the whole neighbourhood for some reason. The battery will be pretty dead tomorrow too i guess
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Have you had the battery load tested?
If it is randomly turning on lights etc has it been subject to any flooding or heavy rainfall?
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Second auxiliary battery??
Petrol Pete
Hardcore MB Enthusiast
Not sure how long your battery is in warranty for , but if it's as short as a year , you have a few weeks to tale it back to where you bought it and have them test/replace it.
oldguy57
MB Enthusiast
Could of course have a faulty component (possibly an alternator not charging ) causing a severe battery drain - not unknown on an MB.
StMarks
MB Enthusiast
If it isn't the battery ( /batteries), then I guess it must be a pretty hefty parasitic drain.
If you have a multimeter, then you can test for that. An auto electrician will know how, and will be familiar with the additional challenges that many modern Mercedes (and increasingly other modern vehicles too) present. However a good overview to start with:
https://www.google.com/url?sa=t&sou...0QFnoECCsQAQ&usg=AOvVaw3-2c3nT4dwcTvWbfR_l0OB
Hth
If you have a multimeter, then you can test for that. An auto electrician will know how, and will be familiar with the additional challenges that many modern Mercedes (and increasingly other modern vehicles too) present. However a good overview to start with:
https://www.google.com/url?sa=t&sou...0QFnoECCsQAQ&usg=AOvVaw3-2c3nT4dwcTvWbfR_l0OB
Hth
Now i have tested the battery and it was close to new condition. It’s not the alternator i checked that. This happened in a very rainy week so i suspect there is water in something but the carpets inside is completely dry. The multimeter says there is contact between - and + so i guess there is a short somewhere no idea how to locate it
StMarks
MB Enthusiast
See my post above.
Finding the source of the parasitic drain is a tedious & methodical procedure.
However once you have located the circuit that is leaking to earth, you can identify what operation it supplies. Knowing that, you will (/may) have a rough idea where to be looking for the cause of the fault.
ChrisPDuck
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A faulty alternator diode pack can cause a significant short to earth. The regulator can be fine, so that the alternator appears to provide the correct charging voltage when running, but when stopped the faulty diode pack can lead to a high current drain - enough to completely drain a good battery overnight. I don't see how it could cause the main beam to come on by itself, but it's worth checking. If you can get to the alternator, you can check it with a multimeter.
