Occupancy Sensor Light Won’t Turn Off: Easy Checks Before Replacement
Lights that stay on with an occupancy sensor are often caused by a long time delay, sensitivity settings, air movement, moving objects, line-of-sight traffic, or an override mode. Start with settings and the room before replacing the sensor.
Match the symptom before you touch anything
Good maintenance starts by describing what the system is actually doing. Use the pattern below to decide where to look first.
| What you see | What it points toward | First move |
|---|---|---|
| Never turns off | Override/false occupancy/device fault | Check mode and environment. |
| Turns off then back on empty | False trigger | Find moving/airflow source. |
| Stays on long | Time delay | Measure actual delay. |
| Only when HVAC runs | Air movement interaction | Observe sensor type. |
| Power cycle helps briefly | Configuration/device fault | Use model reset. |
Tools and preparation
What to bring
- Small screwdriver if settings are accessible
- Manufacturer manual/model number
- Flashlight
Before you start
- Confirm the exact location and complaint.
- Photograph labels, settings, and error codes before changing anything.
- Know how to isolate water, power, or the affected area if needed.
- Follow site-specific PPE, lockout/tagout, ladder, roof, and access procedures.
Step-by-step
Identify sensor type
Find manufacturer/model and PIR, ultrasonic, or dual-tech type.
Check manual override
Some devices can be intentionally locked on.
Time the delay
Leave the room and measure actual shutoff time.
Look for false motion
Fans, banners, plants, curtains, hallway traffic.
Review sensitivity settings
Make small changes and record originals.
Use manufacturer reset if needed
Follow exact model instructions.
Replace only after pattern is understood
Internal wiring replacement belongs to qualified staff as required.
Common mistakes
- Replacing before checking delay
- Turning sensitivity too low
- Ignoring moving decorations
- Guessing programming sequences
- Opening line-voltage box
When to stop and hand it off
- Line-voltage access required
- Sensor/plate hot or discolored
- Circuit behaves abnormally
- Specialty/life-safety control involved
Frequently asked questions
How long should it stay on?
Delay is configurable and varies by design and code strategy.
Can HVAC trigger it?
Air movement or moving objects can contribute with some technologies.
What is dual-tech?
A sensor using two detection methods, often PIR and ultrasonic.
Just lower sensitivity?
Only after identifying false triggers; too low can create missed occupancy.
Related BuildingWrench guides
BuildingWrench provides general educational information for commercial-facility maintenance. Manufacturer instructions, applicable codes, site procedures, and required trade qualifications always take priority.