Door and Window Sensor Troubleshooting

A door, window or garage door sensor is usually a two-piece magnetic contact sensor. When the alarm is set and the door or window is opened, the two magnetic sensors are separated from each other, tripping the alarm.

Door Sensors

Garage Door Sensors

Window Sensors

Related Topics

Door Sensors

If a protected door or window with a sensor is open, you will not be able to arm the system. All doors and windows with sensors must be closed in order for you to arm the security system. If you have ensured that all protected doors and windows are closed, but you are still unable to arm your system, please refer to the Reset System page.

Contact sensors are made up of two pieces, the contact and magnet. The dimensions are about 2/3 inches long by 1/4 of an inch wide. Contacts are usually mounted on the upper part of door frame, and the magnet is mounted on the door itself. Both parts usually will have a spacer underneath if the door and frame are metal. Contact sensors may be hardwired or wireless.

Troubleshooting Surface Sensors/Contacts:
Sending False Signals
  • The gap between the contact and magnet must be no more than ¼ of an inch. A larger space can cause false alarms. This can be caused by:
    • weather changes causing the door frame to expand or narrow
    • damage to the door
    • movement of the sensor or magnet
  • There may be damaged or pinched wiring
Showing Faulted State 
  • The gap between the contact and magnet must be no more than ¼ of an inch. A larger space can cause the zone or point to show faulted. This can be caused by:
    • weather changes causing the door frame to expand or narrow
    • damage to the door
    • movement of the sensor or magnet
  • If you have replaced the door recently, check to ensure that the magnet was retained and attached to the new door.
  • There may be damaged or pinched wiring.
Not Activating
  • The wires may have been damaged or pinched
  • If you have a wireless sensor, the battery may need replacing
Displaying Trouble Condition
  • The wires may have been damaged or pinched.
  • If you have a wireless sensor, check to see that the cover is correctly secured. An incorrectly secured cover may cause the tamper to show the zone faulted.
How to Test  Separate the contact and magnet by opening the door at least an inch. 

Notes for Wireless: Wireless contacts often have a mounting bracket instead of a spacer. The contact is 3/4 of an inch long by 1 inch wide. There is a tab at one end of the contact which can be used to remove the cover and replace the battery. See the Sensor Battery Replacement page.

Rollerball Contacts

Rollerball contacts are a single-piece with a rolling-ball component. These sensors are usually installed on metal door frames, attached on the hinged-side of the door. The device has a Rollerball that moves freely within the contact casing. As the door closes, the ball is pushed inward, closing the circuit. These are usually hardwired devices.

Troubleshooting Rollerball Sensors/Contacts:
Sending False Signals
  • The gap between the frame and the door must be no more than 1/8 of an inch. A larger space can cause false alarms. This can be caused by:
    • Weather changes causing the door frame to expand or narrow. You can fix the door or a tech can add a spacer to compensate for the gap between the frame and the door.
  • Moisture can get into the device causing false signals.
Showing Faulted State 
  • The gap between the frame and the door must be no more than 1/8 of an inch. A larger space can cause false alarms. This can be caused by:
    • Weather changes causing the door frame to expand or narrow. You can fix the door or a technician can add a spacer to compensate for the gap.
  • Moisture may have accumulated in the rollerball.
Not Activating
  • The rollerball may be stuck inside the contact casing due to debris.
  • The contact may have been painted over during remodeling.
  • Wires may be damaged or pinched.
Displaying Trouble Condition
  • The wires may have been damaged or pinched.
  • Moisture may have accumulated in the rollerball.
How to Test  Open the door at least 3 inches to activate the zone or point. 

Garage Door Sensors

The garage door sensor allows you to control and monitor the status of your garage door using your ADT Pulse Touch Screen, Web Portal, Mobile App  or Voice App. Additional information is available in the GD00Z-2 Garage Door Opener & Controller device manual.

Troubleshooting the GD00Z-2 Garage Door Controller & Tilt Sensor:
Problem Possible Cause Corrective Action
The Controller does not flash or beep when activated. No power to the Controller 1. Make sure the power supply is plugged in securely to a live outlet.

2. Make sure the power cord is plugged in securely to the Controller.
The Controller flashes and beeps when activated but the door does not move. Obstruction blocking the door or incorrect wiring. 1. Make sure that there are no obstacles preventing the door from moving.

2. Make sure that the GD00Z-2 connection wires are connected to the proper terminals on the garage door opener. Follow the wires from the garage door opener’s pushbutton wall console to the door opener. This is where the GD00Z-2 connection wires should be connected.
Garage door opens or closes, but the status does not change on the touch screen or mobile app. The Tilt Sensor signal is not being received by the Controller 1. Make sure the Tilt Sensor is mounted correctly on the garage door, with the arrow pointing up.

2. Tilt Sensor battery may need to be replaced. The sensor uses a Type CR2032 coin cell battery and must be installed with the "+" facing up.

3. Make sure the battery pull tab has been removed from the Tilt Sensor.

Window Sensors

Contact sensors are made up of two pieces: the contact and magnet. The dimensions are about 2/3 inches long by 1/4 of an inch wide. The contact is usually mounted on the lower side of a double hung or casement window frame, and the magnet is mounted on the window itself. Contact sensors may be hardwired or wireless.

Troubleshooting Surface Sensors/Contacts:
Sending False Signals
  • The gap between the contact and magnet must be no more than ¼ of an inch. A larger space can cause false alarms. This can be caused by:
    • weather changes causing the window frame to expand or narrow
    • damage to the window
    • movement of the sensor or magnet
  • There may be damaged or pinched wiring
Showing Faulted State 
  • The gap between the contact and magnet must be no more than ¼ of an inch. A larger space can cause the zone or point to show faulted. This can be caused by:
    • weather changes causing the window frame to expand or narrow
    • damage to the window
    • movement of the sensor or magnet
  • The window may not be completely closed.
Not Activating
  • The wires may have been damaged or pinched.
  • If you have a wireless sensor, the battery may need replacing.
Displaying Trouble Condition
  • The wires may have been damaged or pinched.
  • If you have a wireless sensor, check to see that the cover is correctly secured. An incorrectly secured cover may cause the tamper to show the zone faulted.
How to Test  Separate the contact and magnet by opening the window at least one inch. 

Notes for Wireless: Wireless contacts often have a mounting bracket instead of a spacer. The contact is 3/4 of an inch long by 1 inch wide. There is a tab at one end of the contact which can be used to remove the cover and replace the battery. See battery replacement guides.

Related Topics

Testing Your System
Here are instructions for placing your system in Test mode, and for removing it from Test mode once the test is complete.

Door and Window Sensor Battery Replacement
Step-by-step instructions on how to change the battery in your door and window sensor.

Find the Right Sensor Battery
Identify which battery goes with your peripheral sensor.

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