How to Replace the Battery in a Mercedes-Benz S320 Key?
2 Answers
Mercedes-Benz S320 key battery replacement method is: 1. Press the button on the back of the key; 2. Push the back cover of the key forward to open it; 3. Replace the battery in the slot and reinstall the key back cover. Functions of the car key: 1. After the vehicle is turned off, long-press the lock button on the remote key to close the windows; 2. The red horn-shaped button on the key serves both to locate the car and as an emergency function; 3. It has an automatic trunk opening feature. Principle of the car key: The owner emits a weak radio wave, which is received by the car antenna. The electronic control unit (ECU) identifies the signal code, and the system's actuator motor or electromagnetic coil performs the unlocking or locking action.
I've changed the battery in my Mercedes S320 key several times myself, and the process is quite simple. The key is usually a flip-open type, with a small groove on the back. You can gently pry it open using a coin or a thin plastic card. Remove the old battery, typically a CR2032 model, and confirm the correct orientation—place the new battery with the positive side facing up. Be careful not to apply too much force when inserting the battery to avoid damaging the contacts. Then, close the cover back up; a click sound indicates it's locked. After replacing the battery, remember to test if the key works properly. If it doesn't, the battery might be inserted incorrectly or the contacts could be dirty—try cleaning them with a cotton swab and test again. It's best to buy an original CR2032 battery, which is available at regular supermarkets, affordable, and long-lasting. The whole process takes less than five minutes. Doing it yourself saves money and hassle, and you avoid the long wait at the dealership.