How to Replace a Home Alarm Motion Detector

Turn off the alarm system to prevent accidental shorts while replacing the motion detector. Refer to the user's manual that came with the system to find the correct procedure for turning off the alarm panel.

Remove the cover from the existing motion detector. Check for and remove any retaining screws in the cover and pry the cover off.

Make note of the existing wires and the terminals they connect to inside the motion detector. Note also any height and range settings, and any areas that the lens has masked off. Unscrew the terminals screws and pull the wires free.

Remove the mounting screws holding the motion detector to the wall and remove the detector. Pull the wires through the hole in the back or side of the motion detector.

Remove the cover from the replacement motion detector. Make a hole for the wires in the back of the detector in the same place as the hole in the old detector. Adjust the detector settings to match the settings of the old detector and use the included masking material to mask any parts of the lens that the old detector has masked.

Run the wires through the hole in the back of the detector. Mount the detector to the wall using the included screws and the existing mounting holes.

Connect the wires to the same terminals on the replacement motion detector that they were connected to on the old detector. Tighten the terminal screws. Place the cover on the replacement motion detector and install and tighten any retaining screws.

Turn on the power to the alarm system.