Is your 2007 BMW 328i 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 your key fob failing to lock or unlock the doors in cold temperatures, or your car not remembering personalized settings like radio presets, are strong indicators that it’s time for a battery replacement. Don’t worry, replacing the battery in your BMW 328i key fob is a straightforward DIY task that can save you time and money compared to dealership service. This guide will walk you through each step of the 2007 Bmw 328i Key Fob Battery Replacement process.
Before you begin, it’s crucial to understand that the BMW key fob is sealed. This means you’ll need to carefully open it to access the battery. While it might seem daunting, with the right tools and a bit of patience, you can easily complete this repair. Let’s get started on replacing your 2007 BMW 328i key fob battery.
Tools and Materials You’ll Need
- Replacement Battery: You’ll need a VL2020 lithium-ion rechargeable battery. It’s essential to get the correct battery type to ensure proper function and longevity of your key fob. You can find these batteries online, for example, here. Make sure to note the terminal orientation of your old battery before ordering to ensure the new one matches.
- Sharp X-Acto Knife: A sharp X-Acto knife or similar precision knife is necessary to carefully cut open the sealed key fob casing.
- Non-Metallic Pry Tool: A credit card, plastic pry tool, or guitar pick will be helpful to gently apply tension to the battery during desoldering without damaging the circuit board.
- Soldering Iron and Solder: You’ll need a soldering iron to desolder the old battery and solder in the new one. If you’re new to soldering, practice on some scrap electronics first.
- Cyanoacrylate Glue (Gel Type): A gel-type cyanoacrylate glue (like Super Glue gel) is ideal for resealing the key fob housing after the battery replacement. Gel type is recommended because it is less likely to run and get into unwanted areas.
Step-by-Step 2007 BMW 328i Key Fob Battery Replacement Guide
Step 1: Carefully Open the Key Fob Casing
The BMW key fob for your 2007 328i is glued shut, requiring a careful approach to open it without damaging the internal components. Take your sharp X-Acto knife and gently begin cutting along the seam of the key fob. It’s crucial to go slowly and avoid cutting too deep. Multiple shallow passes are better than trying to force it open in one go. Work your way around the entire perimeter of the fob, gradually separating the top and bottom halves.
Step 2: Desolder the Old Battery
Once you have the key fob open, you’ll see the circuit board with the battery soldered in place. To remove the old battery, you’ll need to desolder it. Start by using your non-metallic pry tool (like a credit card) to gently apply a small amount of tension underneath the battery. Focus on the corner terminal first. Apply heat from your soldering iron to the corner terminal of the battery. Once the solder melts, the tension from your pry tool should help lift the terminal. Repeat this process for the other terminal. The corner terminal is recommended to be desoldered first because the middle terminal has a longer lead and is harder to access initially.
Step 3: Solder in the New Battery
Now, take your new VL2020 battery and carefully place it into the battery holes on the circuit board. Hold the PCB by its edges and gently press the battery down into place. Apply heat with your soldering iron to the middle terminal first, allowing the solder to flow and secure the battery. Then, solder the corner terminal in the same way. Ensure the battery is sitting flush against the circuit board and the solder joints are solid.
Step 4: Test and Reassemble
Before fully reassembling the key fob, it’s wise to test if the new battery is working correctly. Dry fit the circuit board back into the key fob housing and test the key functions. Try locking and unlocking your 2007 BMW 328i and check if your personalized settings are restored when you start the car. If everything works as expected, you’ve successfully completed the 2007 bmw 328i key fob battery replacement! If it doesn’t work, double-check your solder connections and battery orientation. If issues persist, there might be a different problem, and consulting a professional might be necessary.
Step 5: Glue the Key Fob Housing Back Together
Finally, it’s time to reassemble the key fob. Apply a small amount of gel-type cyanoacrylate glue to the edges of one half of the key fob housing. Carefully align the two halves and press them firmly together. Hold them together for a few moments until the glue sets. Be sparing with the glue to avoid getting it on the circuit board or buttons.
Congratulations! You’ve successfully completed a 2007 BMW 328i key fob battery replacement. You should now have a fully functional key fob, even in cold weather, and your BMW 328i should remember your personalized settings again. This DIY repair not only saves you money but also provides a satisfying sense of accomplishment. For more DIY car key fob repairs and information, visit keyfobprog.com.
