How to Replace the Battery in an Older Mercedes S Key?

[StJuniper]

Slide open the flap at the rear end of the key to remove the mechanical key. Insert the mechanical key into the side slot of the key holder, press the internal gray button, and with the other hand push the rear end of the key upward. When a gap opens, you can then remove the mechanical key. Detailed steps are as follows: 1. Remove the rear end by hand to replace the battery. After installing the new battery, reinsert the key holder, and the key battery replacement is complete. The lifespan of a Mercedes key battery is generally two years, while the original factory battery can last up to six years. 2. When the key battery is low, the Mercedes will provide two types of alerts: first, pressing the ignition switch will display a "Replace Key Battery" message on the dashboard. Second, pressing the lock or unlock button on the key will cause the indicator light on the key to dim or not light up, indicating it's time to replace the key battery.