Experiencing issues with your 2006 BMW 325i key fob, especially in cold weather? You might find that your key fob struggles to lock or unlock your car, and upon starting, your personalized settings like radio presets are gone. This common problem often points to a depleted key fob battery. Replacing it yourself is a straightforward process, and this guide will walk you through each step.
Step 1: Purchase the Correct Battery
First, you’ll need the right replacement battery. It’s crucial to get the correct type, ensuring the terminals are positioned correctly (approximately 90 degrees offset). The battery you need is a VL2020 lithium-ion battery. You can find suitable replacements online.
Step 2: Carefully Open the Key Fob Casing
The BMW key fob is sealed with glue, so opening it requires patience and care. Using a sharp X-acto knife, carefully cut along the seam of the fob. It’s essential to proceed slowly and avoid cutting too deep to prevent damage to the internal circuit board (PCB).
Step 3: Desolder the Old Battery
Once the fob is open, gently pry the old battery loose using a non-metallic tool. A credit card or plastic pry tool works well to avoid short circuits. Apply slight tension to the battery, and then desolder the corner terminal first. This is important because the middle terminal has a longer lead, making it harder to access initially.
Step 4: Solder in the New Battery
Position the new VL2020 battery into the battery holes on the PCB. Hold the PCB by its edges and gently press down on the battery to ensure it’s properly seated. Apply heat to the middle terminal first, followed by the corner terminal. The battery terminals should push through the existing solder and settle into place.
Step 5: Test the Key Fob
Before sealing the key fob, dry fit the PCB back into the housing and test its functionality. Check if the key fob locks and unlocks the doors and if your car starts correctly and retains your personalized settings. If everything works as expected, proceed to the final step.
Step 6: Reassemble the Key Fob
You have two options for reassembling your key fob. You can purchase a new replacement 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 prevent it from running and potentially gluing the PCB to the housing. Apply the glue to the edges of the fob casing and carefully press the two halves together until they are securely bonded.
By following these steps, you can successfully replace the key fob battery in your 2006 BMW 325i and restore its full functionality, saving yourself a trip to the dealership.
