Say goodbye to unreliable keyless entry with our foolproof guide on key fob battery replacement. We’ve simplified the steps so you can enjoy the benefits of a fully operational key fob without the hassle. Try these instructions out on your BMW 3 Series.
2011 – 2023 Models
- Flip the key fob over and locate the release button or area on the backside. Press the button to remove the internal key from the fob.
- On the side where the key was removed, you’ll find a small hole. Insert a flat-head screwdriver into the hole and gently pry the backing off.
- Once the backing is off, you’ll see the battery. Use a flat-head screwdriver to carefully pop out the old battery.
- Purchase a new CR 2450 battery. You can easily find these batteries online, for example, on Amazon.
- Place the new battery into the battery compartment with the correct orientation.
- After inserting the new battery, carefully put the backing of the key fob back into place. Align it correctly and gently press until it snaps back into position.
- Before using the key fob, test it to make sure the new battery is working correctly.
1998 – 2005 Models
- On the edge of the key fob, you will notice a line that separates it into two halves.
- Using a sharp knife, carefully score and cut through the plastic all the way around the key. Take your time to avoid damage.
- Start cutting from the top of the key, ensuring a clean separation of the two halves.
- Once the key fob is separated, you will see the circuit board inside.
- Remove the circuit board by tapping it out or using small tweezers.
- Locate the rechargeable VL2020 battery on the circuit board; it is connected to the board through two soldered legs.
- Use a soldering iron and a soldering vacuum to desolder the old battery’s legs. Melt the solder and remove it to free the battery.
- Acquire a new VL2020 rechargeable battery with legs offset at 90 degrees.
- Double-check that the new battery’s legs align with the soldering points on the circuit board.
- Place the new battery onto the circuit board, ensuring its legs fit into the soldering points.
- If needed, clear off any excess solder to create space for proper attachment.
- Use the soldering iron to attach the new battery securely to the circuit board.
- Melt solder onto the soldering points and the battery’s legs, ensuring a strong connection.
- Carefully place the circuit board back into its original position within one of the key fob halves.
- The buttons on the circuit board should align with the corresponding buttons on the key fob half.
- Apply a small amount of superglue around the edges of the key fob half that houses the circuit board.
- Realign the two halves of the key fob and press them together firmly, allowing the superglue to bond them.
- Make sure the key fob is securely sealed and there are no gaps.
Test the key fob by pressing the buttons.