Use a screwdriver to lock the door latch. Find a way to secure the switch pushed in. If you are going to keep any of the doors open, manually press the door switch.You may be required to perform a window and sunroof synchronization.You may be required to enter the radio code after this test. Make sure you have the radio code written down.Make sure you have a fully charged battery.Lights including light in the glove boxīefore you start troubleshooting battery drain problems.Top 7 Systems that Cause Battery Drain Problems The Mastech Digital Multimeter is what we use in this guide, it i s capable of reading currents and you can buy it online, click here to check price on Amazon. Multimeters are very inexpensive and be purchased for under $20. The multimeter should be able to read at least a 10 amp current. To troubleshoot the current draw, you need a multimeter that can perform current reading. Even those systems that stay on all the time, draw very little current typically less than 50 milliampere, and should not drain the battery.Ī defective electrical system, Control Unit or a fault on the CAN Bus (Controller Area Network) are also causes that can cause your Mercedes-Battery battery to die. While the electronic equipment in your car should not draw any current when the car is parked there are exceptions such as the security system in your car. One simple example is when lights are left on overnight. You try to start your Mercedes-Benz and the car is either completely dead or this happens:īattery drains happen when electronic equipment (consumer units) are constantly drawing current from the battery while the car is parked. Does your Mercedes-Benz battery slowly drain? Battery is dead every morning? Does the Mercedes-Benz battery die when you have the car parked overnight or leave it parked for a few days? This step by step guide will explain how to troubleshoot this problem, the basics of battery drain problems, why the battery dies overnight, most common trouble spots.

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