How to Replace the Battery in a Mercedes-Benz SL400 Key?
3 Answers
Mercedes-Benz SL400 key battery replacement steps are as follows: 1. Before replacement, check the battery model for the car key, which is usually found in the vehicle's user manual, then select a new key battery according to the specified model. 2. From the end of the key, push up the marked switch, and the hidden mechanical key will pop out slightly, allowing you to remove the mechanical key. 3. Still at the end of the key, use the just removed mechanical key to press against the marked position, apply gentle force, and the key shell can be opened. 4. After removing the key shell, you can see the battery position is relatively deep. Use a small screwdriver to slide into the gap on both sides, gently pry to remove the old battery. 5. After installing the new battery (ensure the positive and negative poles are not reversed), first insert the top of the shell, then press firmly on the other end to complete the battery replacement.
Replacing the battery for a Mercedes SL400 key is actually quite simple, and I managed to do it myself. The first step is to buy a CR2032 coin cell battery, available at supermarkets or online stores for just a few bucks. Next, locate the small slit on the back of the key—I used a small coin or paperclip to gently pry it open, being careful not to apply too much force to avoid cracking the plastic. Once open, carefully remove the old battery, paying attention to the positive and negative markings. When inserting the new battery, make sure the positive side faces up. Finally, snap the cover back on and press firmly, then test the remote function. If it doesn’t work, the battery might be inserted the wrong way. Remember to replace the battery every two years to prevent unexpected issues. The whole process takes just a few minutes, saving both money and hassle—no need to visit a repair shop.
I recently replaced the battery in my Mercedes SL400 key, and it was really not difficult. First, I confirmed the battery model was CR2032 and bought a new one at a hardware store. Then, I picked up the key, found a gap along the edge, and gently pried open the casing with a fingernail or a small knife—taking it slow and steady. After removing the old battery, I inserted the new one with the positive side facing outward, closed the casing, and snapped it shut. Testing the remote locking function confirmed it worked immediately. Doing it myself felt much more convenient than hiring someone, and I even picked up a little skill. If you have similar tools like a small screwdriver, it would be even better. Regular care, such as avoiding exposure to rain or drops, can extend the key's lifespan.
