What is the tutorial for replacing the battery in an old Mercedes SL350 key?
2 Answers
First, flip open the tab at the rear end of the key to remove the mechanical key. Insert the mechanical key into the slot at the tab position and apply slight pressure to pop open the back cover. Then, remove the depleted old battery and replace it with a new one. Close the back cover to complete the key battery replacement. Related instructions are as follows: 1. After installing the new battery, reinsert the key holder to finish the battery replacement. The lifespan of a Mercedes key battery is typically two years, while an original one can last up to six years. 2. When the key battery is low, 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 dims or fails to illuminate, it's time to replace the key battery.
I've replaced quite a few Mercedes key batteries, and the old SL350 model is actually not difficult. There's a small gap on the back of the key - use a flathead screwdriver or plastic card to gently pry open the back cover. Don't apply too much force or the plastic casing may crack. After removing the old battery, note its model (usually a CR2032 coin battery) with the positive side facing up. When inserting the new battery, ensure correct polarity alignment - reversing it will prevent operation. Snap the cover back on until you hear a click. Test the lock button to see if the red indicator light activates; if not, there may be battery quality issues or internal faults. Remember to wash hands beforehand to prevent static electricity and avoid contaminating metal contacts. I recommend purchasing genuine batteries from auto shops to avoid counterfeits, and keeping a spare at home just in case. The whole process saves time and money - just five minutes' work. Regularly check battery life to prevent midnight emergencies when the key dies.
