Is your car key fob starting to feel a little… unresponsive? Do you find yourself pressing the unlock button multiple times before your car finally acknowledges your request? It’s a common sign that the battery in your key fob is likely running low and needs replacing.
Before you rush to a dealership or auto repair shop, you should know that replacing a key fob battery is a surprisingly easy task you can tackle yourself. Not only will you save money on service fees, but you’ll also gain a little DIY satisfaction. This guide will walk you through the simple steps of how to change a battery in your key fob, ensuring you get back to effortlessly accessing your vehicle.
Tools You’ll Need to Replace Your Key Fob Battery
Fortunately, you likely already have most of the tools needed for this minor car maintenance task right at home. Here’s what you’ll need to gather before you begin:
- A small, flat-head screwdriver or a watch knife: This is crucial for carefully prying open the key fob casing. A watch knife, with its thin blade, is often ideal, but a small precision screwdriver will also work. Avoid using anything too large or sharp that could damage the plastic.
- A new replacement battery: Key fobs typically use coin cell batteries, most commonly the CR2032. However, battery types can vary depending on your car’s make, model, and year. We’ll discuss how to identify the correct battery type shortly. It’s a good idea to have a fresh, high-quality lithium battery on hand to ensure longevity.
- A precision screwdriver set (possibly): While not always necessary, some key fobs use tiny screws to secure the casing. A set of precision screwdrivers, ranging from 1.4mm to 2.4mm, will be useful if your fob has screws.
- Tweezers (optional but recommended): Tweezers are incredibly helpful for removing the old battery and placing the new one, especially in tight spaces, without touching the battery terminals with your fingers.
- Your smartphone camera: This is an invaluable tool for taking pictures of the key fob’s internal components before you start removing anything. These photos will serve as a reference guide when you reassemble the fob, ensuring all parts go back in the correct place.
Step-by-Step Guide to Replacing Your Key Fob Battery
With your tools assembled, let’s dive into the process of replacing your key fob battery. Follow these steps carefully to ensure a smooth and successful battery change.
Step 1: Prepare Your Workspace and Gather Your Tools
Find a clean, well-lit workspace. A table or countertop covered with a soft cloth can prevent scratches and keep small parts from rolling away. Have all your tools and the new battery within easy reach.
Step 2: Open the Key Fob Casing
This is often the trickiest part, but with patience and the right technique, it’s quite manageable.
- Inspect the Fob: Look closely at your key fob casing. Many fobs have a small notch or seam line indicating where to insert your prying tool. Some might have tiny screws that need to be removed first – if you see screws, use the appropriate precision screwdriver to remove them and carefully set them aside.
- Use Your Pry Tool Gently: Insert the tip of your flat-head screwdriver or watch knife into the notch or seam. Apply gentle, steady pressure to begin separating the two halves of the casing. Do not force it. Work your tool around the seam, gently prying as you go, similar to peeling an orange.
- Avoid Pulling Apart Forcefully: Once you have a small gap, resist the urge to yank the case open. Continue to carefully work your pry tool around the perimeter of the fob to gradually loosen all the fasteners. Forcing it open can damage the plastic clips and could lead to needing a full key fob replacement.
Step 3: Identify the Battery Type
Once the key fob is open, take a moment to identify the type of battery it uses.
- Check for Markings: Look for markings on the old battery itself or inside the key fob case. Often, the battery type (like CR2032, CR2025, CR2450, or CR1620) is printed directly on the battery. Sometimes, the battery size might be embossed inside the plastic casing of the key fob.
- Consult Your Owner’s Manual (If Necessary): If you can’t find the battery type on the fob or battery, your vehicle’s owner’s manual should specify the correct replacement battery for your key fob.
- Common Battery Types: As mentioned, CR2032 is the most common key fob battery. However, other types like CR2025, CR2450, CR1620, and CR1220 are also used. Honda vehicles sometimes use CR1250 batteries, and some Ford Mustang key fobs require two batteries. Knowing the exact type is crucial to ensure proper function.
Step 4: Remove the Old Battery
Now that you’ve identified the battery type, it’s time to remove the old one.
- Take a Reference Photo (Crucial Step!): Before you remove the old battery, use your smartphone to take a clear picture of the battery compartment. Pay close attention to the battery’s orientation (+ and – sides). This photo will be invaluable when installing the new battery.
- Use Tweezers (Recommended): If you have tweezers, use them to gently lift the old battery out of its compartment. If you don’t have tweezers, you can carefully use your fingertip, but try to avoid touching the flat surfaces of the battery as much as possible to prevent transferring oils.
- Note the Battery Orientation: Observe whether the positive (+) or negative (-) side of the battery is facing up. Your reference photo will be helpful here.
Step 5: Install the New Battery
With the old battery removed, it’s time to install the new one.
- Match the Battery Type: Ensure the new battery is the correct type as identified in Step 3.
- Install with Correct Polarity: Using your reference photo, place the new battery into the compartment with the correct orientation (+ side up or down as needed). Gently press the battery into place until it’s securely seated.
- Avoid Touching Battery Terminals: Again, if possible, use tweezers to handle the new battery and avoid touching the flat surfaces to keep it clean and maintain optimal conductivity.
Step 6: Close the Key Fob Casing
The final step is to reassemble the key fob.
- Align the Casing Halves: Carefully align the two halves of the key fob casing.
- Snap the Case Shut: Press the two halves firmly together until they snap securely back into place. You should hear a click or feel the fasteners engage. If your fob had screws, replace them and tighten them gently.
- Test Your Key Fob: Once the fob is reassembled, test it to ensure it’s working correctly. Try unlocking and locking your car, and test any other functions like remote start or panic button.
Choosing the Right Replacement Battery
Selecting the correct replacement battery is essential for your key fob to function reliably. Here’s a bit more detail on common key fob battery types:
- CR2032: This is the most common type, a 3V lithium coin cell battery known for its long life and reliability. It’s 20mm in diameter and 3.2mm thick.
- CR2025: Similar to CR2032 but slightly thinner (2.5mm thickness), also a 3V lithium coin cell. Sometimes used in slimmer key fobs.
- CR2450: A larger capacity 3V lithium coin cell (24.5mm diameter, 5mm thickness), offering longer life, often found in fobs with more features.
- CR1620 & CR1632: Smaller 3V lithium coin cells (16mm diameter, 2.0mm or 3.2mm thickness respectively), used in very compact key fobs.
- CR1220 & CR1250: Less common but still used, these are smaller 3V lithium coin cells (12.5mm diameter, 2.0mm or 5.0mm thickness).
Always double-check the battery type required for your specific key fob to ensure compatibility and optimal performance.
Important Tips for Key Fob Battery Replacement
Keep these additional tips in mind for a smooth and successful key fob battery replacement:
- Work in a Clean and Organized Area: This helps prevent losing small parts and keeps dirt from getting inside your key fob.
- Be Gentle: Avoid using excessive force when opening the key fob casing. Gentle and patient prying is key to preventing damage.
- Take Pictures: We cannot stress enough the importance of taking photos, especially of the battery orientation and internal components. These visual aids are incredibly helpful during reassembly.
- Don’t Disturb Internal Components: Focus solely on the battery. Avoid touching or moving any wiring or circuit boards inside the fob, as this could cause damage or require reprogramming.
- Dispose of Old Batteries Properly: Lithium coin cell batteries should be disposed of responsibly. Check your local regulations for battery recycling programs.
By following these steps and tips, you can confidently change the battery in your key fob and restore its functionality, saving time and money while gaining a valuable DIY skill.
