What is the tutorial for replacing the battery in an old Mercedes E320 diesel key?
2 Answers
Here are the instructions for replacing the battery in an old Mercedes E320 diesel key: Push open the tab at the rear end of the key to remove the mechanical key. Insert the mechanical key into the side slot of the key groove, press the internal gray button, and with the other hand, push the rear end of the key upward. When a gap opens, you can remove the mechanical key. After replacing the new battery, reinsert the key holder, and the key battery replacement is complete. Additional information: The lifespan of a Mercedes key battery is generally two years, while the original factory battery can last up to six years. When the key battery is depleted, the Mercedes vehicle will provide two types of alerts: one is when you press the ignition switch, the dashboard will display a message to replace the key battery. The second is when you press the lock or unlock button on the key. If the indicator light on the key becomes dim or does not light up, it's time to replace the key battery.
Replacing the battery for an old Mercedes E320 diesel key is actually quite easy. I've done it several times. There's usually a small gap on the side or top of the key. Use a flathead screwdriver or a stiff plastic card to carefully pry open the casing. Inside, you'll find a CR2032 coin cell battery. When removing the old battery, pay attention to the positive and negative terminal positions. When inserting the new battery, make sure the positive side (marked with a +) faces upward and aligns with the slot—don't put it in backward. Close the casing and press firmly. Test the unlock button—if the light comes on or the car responds, you've succeeded.
For tools, use non-slip ones to avoid scratching the key. Choose well-known battery brands like Sony or Panasonic for longer life. Wash and dry your hands before replacing to prevent static electricity. The whole process takes just a minute or two, saving you a trip to the shop. If it gets stuck, gently wiggle it side to side instead of forcing it open.
