Open the key fob and identify the battery type

Most Cadillac key fobs split open along a seam running around the edge. Look for a small slot or notch on the side of the fob — this is where you insert a flathead screwdriver or coin to gently pry the two halves apart. Do not force it; if it resists, you may be pushing in the wrong spot. The seam usually runs horizontally around the middle of the fob.

Once open, you will see a small round or rectangular battery sitting in a plastic holder. The battery type is printed on the top surface — it will be something like CR2032, CR2025, or CR2016. Write down this number before you go to the store, or take a photo of the battery itself. This ensures you buy the exact replacement.

Key Takeaways

  • Cadillac key fobs typically open by inserting a flathead screwdriver into a seam on the side and gently prying the two halves apart.
  • The battery type is printed on the battery itself — common types are CR2032, CR2025, and CR2016 — and you must match it exactly.
  • Coin-cell batteries cost between two and five dollars at pharmacies, grocery stores, and hardware retailers.
  • When reinserting the battery, the positive side (marked with a plus sign) must face upward toward the circuit board.
  • If the fob still does not work after battery replacement, the problem is likely a worn circuit board contact or a broken button, not the battery itself.

Remove the old battery and note its orientation

Gently lift the old battery out of its plastic holder using your fingernail or a plastic spoon. Do not use a metal tool that could scratch the circuit board underneath. As you remove it, notice which side was facing up — this matters for the new battery.

The battery has a plus sign (+) on one side and a minus sign (−) on the other. In a working fob, the plus side always faces upward, toward the circuit board. If your old battery was installed backwards, that is why the fob stopped working. Set the old battery aside; you can recycle it at most pharmacies and electronics retailers.

Buy the correct replacement battery

Take the battery number to any pharmacy, grocery store, or hardware store. Coin-cell batteries are stocked in the watch and battery section, usually near the checkout or in the health and beauty aisle. A replacement battery costs between two and five dollars. You do not need a special tool or a technician — the battery itself is the only thing you need to buy.

If you cannot find the exact type, do not substitute. CR2032 and CR2025 look nearly identical but have different thicknesses, and using the wrong one can prevent the fob from closing properly or damage the contacts. Ask a store employee to confirm you have the right number before you leave.

Insert the new battery with the correct side facing up

Remove the new battery from its packaging. Hold it so the plus sign (+) faces upward. Place it into the plastic holder in the fob, pressing gently until it sits flat. The battery should not require force — if you are pushing hard, you may have it upside down. Flip it and try again.

Double-check that the plus side is facing the circuit board (the side with the electronic components and button contacts). This is the most common mistake. If the battery is backwards, the fob will not work, and you will think the battery is dead when it is actually just installed wrong.

Close the fob and test the buttons

Align the two halves of the fob so the seam matches up evenly. Press them together firmly until you hear or feel a click. The fob should close flush with no gaps. If one side is higher than the other, open it again and make sure the battery is sitting flat in its holder.

Press each button on the fob — lock, unlock, and panic if your model has one — and listen for the car to respond. The doors should lock and unlock, and the lights should flash. If nothing happens, open the fob again and check that the battery is right-side up and sitting completely flat. If the battery is correct and the fob still does not work, the problem is likely worn contacts on the circuit board or a broken button, not the battery.

What to do if the fob still does not work

If you have installed a fresh battery with the correct orientation and the fob still does not respond, the issue is inside the fob itself. The most common culprit is a worn or corroded contact point where the battery touches the circuit board. Over time, these contacts can develop a thin layer of oxidation that blocks the electrical connection.

You can try cleaning the contacts by gently rubbing the top and bottom of the battery with a clean, dry cloth or a pencil eraser, then reinserting it. If that does not work, the circuit board or button contacts may be damaged, and the fob will need professional repair or replacement. Contact a Cadillac dealer or a local automotive locksmith for a replacement fob or repair estimate.

Frequently Asked Questions

Can I use a different battery type if I cannot find the exact one?

No. CR2032, CR2025, and CR2016 are different thicknesses and voltages. Using the wrong type can prevent the fob from closing, damage the contacts, or fail to power the fob at all. Spend the extra minute to find the correct battery — it costs the same and works the first time.

How long does a key fob battery last?

Most coin-cell batteries last three to four years in a key fob, depending on how often you use it. If you press the buttons multiple times a day, the battery may last only two to three years. There is no way to predict the exact lifespan, so replace it as soon as the fob stops responding.

What if the fob will not open?

Try inserting the screwdriver or coin into the seam at different points around the edge. Some fobs have the seam on the side rather than the top. If you still cannot open it, do not force it — take it to a Cadillac dealer or locksmith, who can open it without breaking the plastic.

Is it safe to handle the battery with my bare hands?

Yes. Coin-cell batteries are safe to touch. You do not need gloves. However, avoid touching the battery contacts with wet hands, and wash your hands after handling it if you have any cuts or open sores, since the battery contains a small amount of lithium.

Can I replace the battery myself, or do I need a technician?

You can replace it yourself in under two minutes. No special tools or training are required — just a flathead screwdriver or coin and the correct battery type. If the fob will not open or the new battery does not work, then a technician can help, but the battery replacement itself is a straightforward task.