Like anything else relying on a battery, you car key fob can die—often at the worst time. Thankfully, these batteries are easy to replace.

The key fob is your lifeline to your car, letting you unlock the doors and set off the alarm, at a minimum, but how can you tell if it needs a new battery?

How to replace car key battery Most key fobs have a little slot you can use to pop them open with a small flatheaded screwdriver, a butter knife or another key.

Pop out the battery, replace it with a new #2032 battery (positive side down), the clip the key back together and refit the manual key. If your key is brand new to your car you will now need to look ...