Mercedes GLS starting issues and flickering lights

I have a similar GLS The symptoms you describe do sound like a battery issue Low battery voltage can definitely cause those problems A defective battery sensor could explain why the battery isn't maintaining its charge The sensor monitors battery health and informs the charging system If it's sending incorrect data, the battery charge might be insufficient I had similar issues, could you elaborate on how you tested the battery charge

Thank you for your input When testing the battery charge, I used a standard multimeter connected directly to the battery terminals with the engine off I observed a voltage reading of approximately 12.1 volts, which I understand is below the ideal range for a fully charged 12V battery I performed a parasitic draw test as well, but the results seemed normal Considering your experience, do you think it's worth replacing the battery sensor first, or should I explore other possibilities

Given your voltage reading and the fact that you performed a parasitic draw test, it seems likely that the battery sensor is the culprit In my case, the sensor was indeed the cause of the problem Replacing it resolved the weak battery and flickering lights However, I would recommend taking your vehicle to a qualified workshop for a proper diagnosis They can confirm whether the battery sensor is indeed defective and advise on the best course of action

I appreciate the advice It seems prudent to have a professional diagnosis I took it to a workshop, and the battery sensor was indeed faulty The replacement cost was 315€ Since the replacement, the starting issues and flickering lights have vanished It seems the battery is maintaining a proper charge now Thank you for your assistance