Tutorial on Replacing the Battery in an Older Mercedes SL400 Key
2 Answers
Method for replacing the battery in an older Mercedes key: 1. Before replacement, it is best to first understand the battery model of the car key, then select a new key battery according to the specified model. 2. Push the marked switch upward from the tail of the key, and the hidden mechanical key will pop out slightly, allowing you to remove the mechanical key. 3. Still at the tail of the key, use the just-removed mechanical key to press against the marked position, and with a slight force, the key shell can be opened. 4. After opening the key shell, you can see that the battery position is relatively deep. Insert an object along the gaps on both sides, gently pry, and the old battery can be removed. 5. Install the new battery, ensuring the positive and negative poles are not reversed. Then follow the installation steps: insert the top of the shell first, then press firmly on the other end to complete the battery replacement. Finally, don't forget to reinsert the mechanical key.
I've figured out how to replace the battery in an older Mercedes SL400 key. There's usually a small gap at the back of the key. Use a thin tool like a plastic card to gently pry it open—avoid metal to prevent scratching the casing. The battery model is CR2025, which you can buy for just a few dollars at the supermarket. When opening it, pay attention to the orientation of the old battery, and insert the new one in the same direction, with the positive side aligned to the marking on the circuit board. After reassembling, test the remote locking function from a distance. If you encounter any difficulty, don't force it to avoid breaking the clips—it's better to watch an online tutorial for guidance. The battery typically lasts one to two years; opting for branded ones can extend its lifespan. Avoid exposing the key to high temperatures in daily use to prolong battery life. Doing it yourself is both convenient and cost-effective—just prioritize safety.
