The motion detector flashes red


Modern motion detectors with electronic components often have a small LED that can flash in some situations. We have summarized for you what a red blinking LED with a motion detector can be for you in the following guide.

Motion detectors can be partially controlled

Modern motion detectors can do more than just trigger a simple circuit. For this, the detectors must be equipped with an electronic control. Some motion detectors can be integrated into the smart home and thus operated via an app. Other less complicated motion detectors provide a simple programming code.

For this the small LED light is needed. For many motion detectors this LED may be red but also blink in green and other colors. As a rule, either an error is displayed or a specific setting of the detector is made.

Unfortunately, it is not possible to give a blanket answer, which is why your motion detector flashes red. For this you need the operating instructions of the manufacturer. In it you can read which flashing codes and flashing colors your motion detector uses.

Possible causes of red flashing light with simple detectors

In certain cases, it can be a simple error message. So there may be several causes why your motion detector is not working properly and then visualizing a red blinking code:

  • connected incorrectly
  • bad cable connection (eg corrosion)
  • unsuitable consumer (power consumption in watts of the consumer does not fit)

Consumers with too high power consumption

In particular, a consumer who needs too high a power output, can quickly trigger an error message, so that the motion sensor flashes red. Therefore, each motion detector is described with the power range in watts, in which the circuits are carried out without problems.

Error codes when operating an LED consumer

Motion detectors with LED bulbs connected as consumers can quickly output an error code. Simple motion detectors are just equipped with the circuit. However, since current is applied to motion detectors permanently, it may be that a certain residual current is forwarded to the consumer.

Similar problem with light switches and LEDs when L is directly applied

Connected LED bulbs can react as if, in a circuit between light switch and consumer without motion detector, the phase L (current leading) is not turned off via the switch, but the neutral conductor N.

The phase is then directly at the consumer. According to VDE, this installation is permissible, but completely unsuitable for LED bulbs, as they will be permanently dim. This corresponds to regular operation, 24 hours a day. In other words, the lifetime of the LEDs is significantly reduced.

High-quality motion detector with interruption relay

If LEDs are to be connected to a motion detector, make sure that no residual current reaches the load. Therefore, high-quality motion detectors are additionally equipped with a relay which switches the circuit only when the motion detector switches.

Tips & Tricks

In the house journal, we offer you numerous guides and instructions on the subject of motion detectors. So you can also read here, which defects can occur on a motion detector.


Video Board: Red Flashing Light on a Honeywell Motion Sensor Means Walk Test