Is your 2009 BMW 528i key fob acting up, especially when the weather gets cold? You might be experiencing the common issue of a dying key fob battery. Symptoms like reduced range, intermittent locking/unlocking, or loss of personalized car settings are telltale signs. Before you rush to a dealership and spend a significant amount, consider this straightforward DIY fix: replacing the battery yourself. This guide will walk you through replacing the 2009 BMW 528i key fob battery, saving you time and money.
First, you’ll need to purchase the correct replacement battery. For the 2009 BMW 528i key fob, you’ll need a VL2020 lithium-ion battery. It’s crucial to note the battery terminal orientation when purchasing, as they are offset at approximately 90 degrees. You can find these batteries online from retailers like eBay or specialized battery stores. Ensure you are buying a genuine VL2020 battery to guarantee optimal performance and longevity for your BMW key fob.
Once you have the new battery, the next step is to carefully open your BMW key fob. The fob is glued shut, so you’ll need a sharp X-acto knife. Gently score along the seam of the fob. Patience is key here; avoid cutting too deep to prevent damage to the internal circuit board (PCB). Work your way around the entire perimeter of the key fob until you can pry it open.
With the key fob open, you’ll see the battery soldered to the PCB. To remove the old battery, use a non-metallic tool like a credit card to gently apply pressure under the battery. This will create a slight gap, allowing you to desolder the corner terminal first. A soldering iron will be needed to melt the solder. Focus on the corner terminal initially, as the middle terminal has a longer lead and is harder to access until the corner is free.
Now, insert the new VL2020 battery into the designated holes on the PCB. Hold the PCB firmly by the edges and gently push the battery down to ensure the terminals protrude through the solder points. Apply heat with your soldering iron to the middle terminal first, then the corner terminal. The heat will melt the existing solder, securing the new battery in place. Ensure a solid solder connection for reliable performance.
Before permanently sealing the key fob, dry fit the PCB back into the housing and test the key functions on your 2009 BMW 528i. Check if the lock, unlock, and trunk release buttons are working correctly. Also, start your car to confirm the personalized settings are restored. If everything is working as expected, you’ve successfully completed the 2009 Bmw 528i Key Fob Battery Replacement!
Finally, you can either purchase a new key fob housing for a fresh look or 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 or gluing the PCB to the housing. Apply a small amount along the seam and press the two halves of the key fob together until the glue sets. With a bit of careful work, you’ve successfully replaced your 2009 BMW 528i key fob battery and restored its functionality.
