Is your 2007 BMW 328xi key fob acting up, especially when the temperatures drop? You’re not alone. Many BMW owners experience issues with their key fobs in cold weather, from failing to lock or unlock doors to losing personalized settings like radio presets. Often, the culprit is a simple fix: a dead or dying key fob battery. Instead of heading to the dealership and spending a hefty sum, you can easily tackle this 2007 Bmw 328xi Key Fob Battery Replacement yourself. This guide will walk you through each step to replace your BMW key fob battery, saving you time and money.
Before we begin, it’s important to understand why this happens. BMW key fobs for models like the 2007 328xi use rechargeable batteries. Over time, these batteries degrade and lose their ability to hold a charge, particularly in extreme temperatures. When your 2007 BMW 328xi key fob battery weakens, you might notice symptoms like reduced range, inconsistent operation, or the dreaded loss of personalized settings.
This DIY guide focuses on replacing the battery in your 2007 BMW 328xi key fob. We’ll use readily available tools and a replacement battery to get your key fob working like new. Let’s get started.
Step 1: Procure the Correct Replacement Battery
First things first, you’ll need the right battery. For a 2007 BMW 328xi key fob battery replacement, you’re looking for a VL2020 battery. It’s crucial to get the correct type to ensure compatibility and proper function. Pay close attention to the battery terminals – they should be offset at approximately 90 degrees, matching your original battery’s configuration.
You can find these VL2020 batteries online from various retailers. A quick search for “VL2020 battery” or “BMW key fob battery VL2020” will provide you with options. Make sure to purchase from a reputable source to guarantee you’re getting a quality, new battery.
Step 2: Carefully Open the Key Fob
Now for the delicate part: opening your BMW 328xi key fob. These fobs are notoriously sealed, glued shut to prevent tampering and moisture damage. You’ll need a sharp X-acto knife or a similar precision cutting tool. Patience is key here. Work slowly and carefully around the seam of the key fob.
Important: Do not cut too deep! The circuit board (PCB) is located just beneath the surface, and you risk damaging it if you apply too much pressure or cut too deeply. Multiple shallow passes are much safer than trying to force it open in one go. Go around the entire perimeter of the key fob, gently separating the top and bottom halves.
Step 3: Desolder the Old Battery
With the key fob open, you’ll see the PCB and the old battery. To remove the old 2007 BMW 328xi key fob battery, you’ll need to desolder it. For this, you’ll need a soldering iron and ideally some desoldering wick or a solder sucker, although careful use of the soldering iron alone can suffice.
Before applying heat, use a non-metallic pry tool, like a credit card or plastic spudger, to gently apply a small amount of tension to the battery. This will help lift the terminal once the solder melts. Start with the corner terminal of the battery. Apply heat to the solder joint until it melts, and gently pry up that corner of the battery. Repeat for the other terminal. The corner terminal is easier to access first because the middle terminal has a longer lead, making it harder to get under initially.
Step 4: Solder in the New VL2020 Battery
Now it’s time to install the new VL2020 battery for your 2007 BMW 328xi key fob battery replacement. Place the new battery into the battery holes on the PCB. Hold the PCB by its edges and gently push the battery down into place. The battery terminals should protrude through the solder pads on the PCB.
Apply heat to the middle terminal first, allowing the solder to reflow and secure the battery in place. Then, repeat for the corner terminal. Ensure the battery is sitting flush against the PCB and the solder joints are solid.
Step 5: Test the Key Fob
Before sealing everything back up, it’s crucial to test your 2007 BMW 328xi key fob battery replacement. Dry fit the PCB back into the key fob housing halves. Go to your BMW 328xi and test the key fob’s functions: locking, unlocking, and starting the car.
Check if your personalized settings are now being recognized. If everything works as expected, congratulations! You’ve successfully completed your BMW 328xi key fob battery replacement. If it doesn’t work, double-check your soldering and battery orientation, but unfortunately, troubleshooting beyond this point is outside the scope of this guide.
Step 6: Reassemble the Key Fob
Finally, you need to reassemble your BMW key fob. You have a couple of options here. For a perfect finish, you can purchase a new key fob housing. This will give your key fob a fresh, unscratched look.
Alternatively, if you’re not concerned about aesthetics, you can simply glue the old housing back together. Use a gel-type cyanoacrylate glue (super glue) sparingly. The gel type is less likely to run and make a mess. Apply a thin bead of glue along the seam and carefully press the two halves of the key fob together. Hold them firmly until the glue sets. Avoid getting glue on the PCB or inside the buttons.
With that, your 2007 BMW 328xi key fob battery replacement is complete! You’ve saved yourself a trip to the dealer and gained the satisfaction of a successful DIY repair. Enjoy your fully functional key fob, even in cold weather!
