Is your 2011 BMW 328i key fob acting up, especially when the weather gets cold? You’re not alone. Many BMW owners experience issues like reduced range or unresponsive buttons in colder temperatures. Often, the culprit is a weak key fob battery. Fortunately, replacing it yourself is a straightforward process. This guide will walk you through replacing the battery in your 2011 BMW 328i key fob, saving you a trip to the dealership.
Before you begin, you’ll need a few items:
- Replacement Battery: You’ll need a VL2020 lithium-ion rechargeable battery. It’s crucial to get the correct battery with the terminals in the right position. You can find these online – search for “VL2020 battery BMW key fob”.
- Sharp X-Acto Knife or Precision Blade: For carefully opening the key fob casing.
- Soldering Iron and Solder: To desolder the old battery and solder in the new one.
- Non-Metallic Pry Tool (Credit Card or Plastic Spudger): To gently apply pressure when desoldering.
- Safety Glasses: To protect your eyes during soldering.
Let’s get started with the battery replacement:
- Opening the Key Fob: The BMW key fob is sealed with glue, so you’ll need to carefully cut it open. Using your sharp X-Acto knife, gently score along the seam line of the key fob. Work slowly and avoid cutting too deep to prevent damage to the internal circuit board (PCB). Patience is key here. Gradually increase pressure until the fob begins to separate. Work your way around the entire seam until you can pry the two halves apart.
- Desoldering the Old Battery: Once the fob is open, you’ll see the PCB with the battery soldered to it. To remove the old battery, you’ll need to desolder it. It’s recommended to start with the corner terminal. Use a non-metallic pry tool, like a credit card, to apply slight upward pressure to the battery. Apply heat to the corner solder joint with your soldering iron until the solder melts and you can lift the terminal. Repeat this for the other terminal to fully remove the old battery.
- Soldering the New Battery: Place the new VL2020 battery into the designated holes on the PCB, ensuring the polarity is correct (match the orientation of the old battery). Hold the PCB by its edges and gently push the battery down into place. Apply heat to the battery terminals from the solder side of the PCB. The existing solder should melt and secure the new battery in place. Start with the middle terminal, then solder the corner terminal for a secure connection.
- Testing and Reassembly: Before sealing the key fob, dry fit the PCB back into the housing and test the key fob functions on your 2011 BMW 328i. Check if the lock, unlock, and trunk buttons are working. Also, start your car to ensure the key is recognized and your personalized settings are restored. If everything works correctly, you can reassemble the key fob. You can purchase a new key fob shell for a fresh look, or simply glue the existing halves back together using a small amount of gel-type cyanoacrylate glue. Apply the glue sparingly to avoid getting any on the PCB.
Congratulations! You’ve successfully replaced the battery in your 2011 BMW 328i key fob. This DIY fix can save you money and restore the convenience of your key fob, especially during those cold winter months. Enjoy the reliable performance of your key fob once again.
