As with many technical advancements, they’re a blessing and a curse. Key fobs are a wonder when your arms are full and you need to open the car doors, trunk or rear hatch. It’s also nice, on a stormy day when you forgot to lock the car doors that you can lock them while looking out at the car from the warmth and comfort of your home or office. But, they’re a frustration when you find yourself pressing the button repeatedly and nothing happens. It’s just no fun when a good key fob goes bad.

You may not think about it but there is a small battery inside your key fob that energizes the device and connects it to the door-lock mechanism in your car. Typically, that connection is good to about 50 feet.

As with any battery, the energy within is not infinite. Yes, car batteries can work for years. But, they are constantly recharged by the car’s alternator, or so we hope. The little battery in your key fob will last until all of the energy inside is used up.

How do you know when your car key fob’s battery is running low?

• Click-and-Click-and-Click: If you find yourself repeatedly pressing the buttons to lock or unlock the doors, open the trunk and turn on the alarm (some key fobs will also start the car when it is equipped with remote start), there’s a good chance that the battery is losing its mojo.
• How Close will you get: If you have to get closer and closer to the car, than you were used to getting, this is also a clue to a weak battery. That 50-feet where the key fob was designed to work becomes 40, then 30, and even 20 feet. It’s time to replace the battery, at least as a first step to making sure your key fob is still operating properly.
• Consistently Inconsistent: Sometimes it works, sometimes it doesn’t? This is also a good sign that the battery in your car’s key fob is drained of its energy. This kind of inconsistency is frustrating. Replace the battery and the problem may go away.

The last sentence above is the key to checking if a good key fob has gone bad. Batteries are relatively inexpensive and easier to replace than you might think. There is usually a small Philips screw in the back of the fob. Remove the screw (being careful not to drop and lose it – i.e., don’t hold it over the sink while removing the screw). Use a flat screwdriver to pry open the key fob, remove the battery and replace it with the same type of battery.

Of course, it is possible that there is something else wrong with the key fob. However, they are amazingly durable and reliable. As long as you don’t run it over with the car, and even then they may survive, if your car’s good key fob has gone bad, it’s probably just the battery.