The Liftmaster 371LM is a garage door system with a single-button remote control. Although the garage door system itself does not use batteries, its remote does. The remote uses a lithium battery and should hold up for about five years. Replacing the 371LM's battery takes less than five minutes and requires no special expertise. You can purchase the proper replacement battery at many electronics stores.
Things You'll Need
Flathead screwdriver (optional)
3V2032 lithium battery
Set the 371LM remote on a table. Slide the metal clip upward to remove it from the back of the remote. If your clip is missing, grab a flathead screwdriver to use instead.
Pry around the seam where the top half of the remote connects with the bottom half. Use the clip or the flathead screwdriver. Work your way around the remote until the top half comes free. Lift it to remove it from the bottom half.
Remove the lithium battery from the compartment. Place the new battery inside with the "Positive" end pointing up.
Place the top half of the 371LM remote onto the bottom half. Push down firmly to snap the top half back into the bottom half. Test the remote to make sure it works.