Motion Sensor Light Stays On: Causes and How to Fix It
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A motion light that never turns off is stuck in one of three states: it’s been put into a manual mode, it’s being re-triggered continuously, or its sensor or relay has failed. Check them in that order.
1. It’s in manual override mode
Many motion-sensor fixtures have a manual “always on” mode that you enter by flipping the wall switch off and back on quickly (typically within a couple of seconds). The light then stays on until dawn or until you reset it. This is easy to trigger by accident.
Fix: turn the wall switch off, wait about a minute, then turn it back on. The fixture should return to automatic mode. Your manual will give the exact timing.
2. The timer is set to maximum
The TIME dial controls how long the light stays on after the last detected motion, from a few seconds up to 10–20 minutes on many models. If it’s at maximum and there’s occasional motion, the light can seem to stay on permanently. Turn it down and see how to adjust motion sensor light settings.
3. Something keeps re-triggering it
Every detection restarts the timer. A heat source, a branch moving in the wind or traffic in view can keep it on all night. Work through why an outdoor motion sensor keeps triggering.
A quick test: cover the sensor completely with a box or a thick cloth. If the light turns off after the timer runs out, the sensor is working and something in view is triggering it. If it stays on, read on.
4. The daylight (lux) setting is wrong
The LUX or dusk dial sets how dark it must be before the sensor activates. On some fixtures the extreme setting enables a dusk-to-dawn mode. Check that the dial isn’t at that position.
5. The sensor is in test mode
Some fixtures have a TEST position that ignores daylight and uses a short timer for setup. Others enter test mode for the first few minutes after power is applied. Move the dial out of TEST.
6. Water got in, or the sensor failed
Moisture inside the sensor head, a lightning surge or old age can leave the relay stuck closed, so the lamps stay powered. Signs: the light stays on even with the sensor covered, and resetting at the breaker doesn’t help. Replace the sensor module (where the fixture allows) or the fixture.
7. Wiring
If the fixture was recently installed or replaced, check that it’s wired as the instructions specify. Swapping the switched and load conductors, or wiring past the sensor, keeps the lamps permanently on. Turn off the breaker before opening anything, and use an electrician if you’re unsure.