Troubleshooting Common Door & Window (contact) Sensor Issues

Summary: If your door/window contact sensor shows low battery, tamper warnings, false alarms, or stops responding, this guide walks you through clear, step-by-step troubleshooting that works across most panels (Qolsys IQ4/IQ2 and 2GIG GC2/GC3). For extra help, text 469-513-8685.

Table of Contents

Common Terms

Sensor (Contact Sensor)
Device on a door or window reporting open/closed status to the panel.
Magnet (Strike)
Small piece that aligns with the sensor to register “closed.”
Tamper Switch (Cover Switch)
Internal switch that triggers if the sensor housing is removed.
Battery (Cell)
Power source inside the sensor (type varies by model—check your manual).
Bypass (Exclude)
Manual disabling of a sensor so it won’t trigger alarms.

Alarm Triggered

If your sensor causes an unexpected alarm:

  1. Verify no one opened the door/window.
  2. Open the sensor housing; align the magnet within ¼ inch of the sensor body.
  3. Remove vibration or draft sources (fans, winds, heavy traffic).
  4. On your panel:
    • Qolsys: Tap Security > Reset.
    • 2GIG: Press Off > Reset.
  5. Test by opening/closing the door again.

Low Battery Warning

Your panel shows a low battery alert when sensor power is low. To replace:

  1. Remove the sensor from its mount (slide or unclip).
  2. Open the housing to access the battery.
  3. Replace with the correct type (CR2032, CR123A, etc.), matching polarity.
  4. Snap the housing closed until it clicks.
  5. On your panel:
    • Qolsys: Go to Devices > select the sensor > verify alert cleared.
    • 2GIG: Go to Zones > select the zone > verify status.

Sensor Tamper Warning

Displayed when the cover switch is triggered:

  1. Press the cover firmly until it snaps flush.
  2. Inspect for cracks—replace cover if damaged.
  3. Clear the alert:
    • Qolsys: Tap Alerts > Clear All.
    • 2GIG: Tap Trouble icon > find “Tamper” > press OK.
  4. If still triggered, re-enroll the sensor:
    1. Navigate to Devices or Zones.
    2. Select the sensor/zone > Delete > confirm.
    3. Select Add Device or Add Zone and follow prompts.

Sensor Malfunction

When the sensor stops reporting status:

  1. Ensure magnet and sensor are aligned within ½ inch.
  2. Clear any debris between them.
  3. Power cycle your panel:
    • Qolsys: Swipe down > Settings > Advanced Settings > Power Down; wait 2 minutes; power back on.
    • 2GIG: Press Tools > Power Down; wait 2 minutes; press side power button.
  4. If still unresponsive, remove and re-enroll the sensor (see Tamper Warning steps).

Sensor Bypassed

A bypassed sensor is ignored by the system. To re-enable:

  1. Disarm your system.
  2. Open bypass settings:
    • Qolsys: Tap Security > Bypassed Devices.
    • 2GIG: Tap Menu > Bypassed Sensors.
  3. Select the sensor > tap Un-bypass or toggle off.
  4. Re-arm and test the sensor by opening/closing the door.

Tamper Events Disabled

If you’re not seeing tamper alerts, turn them back on:

  1. Open sensor settings:
    • Qolsys: Tap Settings > Sensor Settings.
    • 2GIG: Press Menu > System Configuration > Zones > select zone > Options.
  2. Toggle Tamper Alerts to On.
  3. Ensure sensor housing is firmly mounted so the tamper switch engages.
  4. Exit to save.

Additional Support

If your sensor still misbehaves, our Brinks Home™ Support team is here to help. Call 469-391-4024 or visit our Help Center.

Your home’s security is our priority—let us guide you every step of the way!