How to Replace Key Fob Battery in a Ford Mustang

Did your car’s key fob die? Before you buy a new one, it might just be the battery. In this article, we will walk you through the step-by-step process of replacing the key fob battery in your Ford Mustang, so you can continue to enjoy your keyless entry system again.

2015 – 2023 Models

1. Determine the type of battery you need. Most Ford Mustang key fobs use a CR2032 coin battery.
2. Locate the small button on the back of the key fob and press it to release the metal key.
3. Use a flathead screwdriver to gently pry open the key fob case.
4. Remove the old battery from the key fob.
5. Insert the new battery into the key fob with the positive (+) side facing up.
6. Close the key fob case and snap it back together.

Note: Some Ford Mustang key fobs may require the use of a Phillips head screwdriver to remove the back cover instead of a flathead screwdriver. 

2005 – 2014 Models

1. Make sure you have the correct key fob with the rounded key design used in Ford Mustangs from 2010 to 2014.
2. Identify that the key fob has a built-in smart key functionality.
3. Look for a seam on the side of the key fob that appears to split it in half. The seam should run all the way around the key fob.
4. Use a razor blade or any sharp tool to gently score the edges of the seam.
5. Apply some pressure at the top of the key fob, where you would usually attach a key ring to create leverage.
6. Slowly work your way around the key fob, increasing the separation between the two halves.
7. If needed, use a small flathead screwdriver to further pry open the key fob. As you work around the key fob, you will notice the two halves start to come apart slightly.
8. Keep working until the key fob completely separates into two parts.
9. Once the key fob is in two pieces, you will see a small battery cover in one of the halves.
10. Remove this battery cover to access the battery.
11. Locate the CR2032 battery inside the key fob.
12. If the battery doesn’t easily come out, use a small tool to gently lift it and replace it with a new CR2032 battery.
13. The positive side of the battery faces up towards you (the positive side usually has lettering on it).
14. Place the rubber piece that covers the battery back into position, ensuring it fits properly.
15. Align the two halves of the key fob back together.
16. Carefully snap the two pieces together until they are firmly connected.

Make sure the buttons respond as expected and the smart key functionality is operational.