How to Install Garage Door Security Magnetic Contacts

Open the garage door and wedge a wood block beneath to keep it open. Place the "L" bracket against the inside bottom of the garage door so the attached magnet is facing down. Screw the bracket to the door with wood screws using a Phillips screwdriver.

Place the magnetic contact switch plate on the floor, directly beneath the magnet. Remove the wood block and gently close the garage door to ensure the two will make contact. Raise the garage door and place the wood block back across the bottom to keep the door open.

Draw a line against one side of the magnetic contact switch plate with a pencil. Lift the plate up. Wipe the space beneath the plate with a paper towel to remove loose dirt and other contaminants. Apply bonding glue to the bottom of the plate. Place the plate back on the floor, beneath the magnet, so it lines up with the pencil mark made earlier.

Press down on the plate. Release the plate after a minute has passed so the bonding glue can take hold.

Run the metal-clad cable attached to the magnetic contact switch plate across the length of the floor beneath the garage door. Affix the cable to the floor with silicone paste squeezed out of a silicone sealant tube. The exposed wires at the end of the cable can now be connected to a wired security system.