Experiencing issues with your 2008 BMW 328i key fob, especially in cold weather? It’s a common problem where the key fob becomes unresponsive, failing to lock or unlock your doors remotely. You might also notice your car starting but losing personalized settings like radio presets. Often, the culprit is a weak or dead key fob battery. Fortunately, replacing it yourself is a straightforward process you can tackle at home. This guide will walk you through replacing your 2008 Bmw 328i Key Fob Battery, saving you a trip to the dealership.
Before you begin, ensure you have the correct replacement battery. The 2008 BMW 328i key fob typically uses a VL2020 lithium-ion rechargeable battery. You can find these online from various retailers. Pay close attention to the battery terminal orientation when purchasing, as they need to match your existing battery layout.
Once you have your new battery, follow these steps to replace it:
- Carefully Open the Key Fob: The BMW key fob is sealed tight. Using a sharp X-acto knife, carefully slice along the seam of the fob to pry it open. Work slowly and apply gentle pressure to avoid cutting too deep and damaging the internal circuit board (PCB).
- Desolder the Old Battery: With the fob open, you’ll see the battery soldered to the PCB. Use a non-metallic tool, like a credit card or plastic pry tool, to gently apply a small amount of upward pressure to the battery. Then, using a soldering iron, desolder the corner terminal of the battery. Desoldering the corner terminal first makes it easier to access the other terminal.
- Solder in the New Battery: Place the new VL2020 battery into the battery holes on the PCB. Hold the PCB firmly by the edges and gently push the battery down into place. Apply heat with your soldering iron to the middle terminal first, then the corner terminal. The battery terminals should push through the existing solder and seat properly.
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Test and Reassemble: Before sealing the key fob, dry fit the PCB back into the housing and test the key fob functions. Check if the lock/unlock buttons work and if your car recognizes your personalized settings after starting. If everything is working correctly, you’ve successfully replaced your 2008 BMW 328i key fob battery!
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Seal the Key Fob: You have a couple of options for reassembling your key fob. You can purchase a new key fob housing for a fresh look. Alternatively, you can simply glue the original housing back together. If you choose to glue it, use a gel-type cyanoacrylate glue sparingly to avoid it running and potentially damaging the PCB. Apply the glue to the edges of the housing and press firmly to seal.
By following these steps, you can easily replace your 2008 BMW 328i key fob battery and resolve common key fob issues, getting you back on the road with a fully functional key.
