Most garage doors have a pair of photoelectric sensors that communicate via an invisible infrared beam. One is a transmitter, and the other is a receiver. If something interrupts that beam—or if the sensors aren’t aligned properly—the door won’t close, and the opener may flash or reverse direction.
Each sensor typically has a small LED light that helps diagnose issues. The meaning of these lights varies slightly by brand, but there are general rules that can help you interpret them.
Common Sensor Light Colors and What They Mean
1. Solid Green or Red Light
- What it means: The sensor is receiving power and aligned properly.
- Action needed: None. This is a sign that your sensors are working correctly.
Many systems show a green light on one sensor (receiver) and a red or amber light on the other (transmitter)—both should be solid.
2. Blinking or Flickering Light
- What it means: The sensors are misaligned, or the beam is being obstructed.
- Action needed:
- Check for dirt, dust, or spider webs on the lens
- Make sure both sensors face each other directly
- Look for anything blocking the beam, such as bikes, garden tools, or debris
A blinking light is the most common sensor issue—and usually the easiest to fix.
3. No Light at All
- What it means: The sensor isn’t receiving power or has failed.
- Action needed:
- Check the wiring for any signs of damage
- Ensure the sensor is securely connected
- Inspect the garage opener’s power source and fuse
- Try unplugging and resetting the opener
If the light still doesn’t come on, the sensor may need to be replaced.
What to Do When the Door Won’t Close
If your garage door won’t close and the sensor lights are blinking or off:
- Clean the sensors with a soft cloth
- Realign them until both lights turn solid
- Try closing the door again
If the issue persists, you may need professional help to inspect the wiring or sensor units.
Sensor Light Color Variations by Brand
Here’s a quick look at how sensor lights vary across popular garage door opener brands:
- LiftMaster/Chamberlain/Craftsman: Solid green and amber lights indicate alignment
- Genie: Solid red lights typically indicate proper alignment; flashing red means misalignment
- Overhead Door: Solid green or red means aligned; blinking indicates a beam interruption
Always refer to your product manual for brand-specific meanings.
When to Call the Professionals
If you’ve cleaned and realigned the sensors but still have problems, it’s best to contact a qualified technician. Sensor issues can stem from faulty wiring, moisture damage, or malfunctioning circuit boards.
At Four Seasons Garage Doors, we provide fast and affordable sensor repairs and replacements throughout Illinois.
Garage Door Sensor Maintenance Tips
- Clean the sensors regularly to prevent false readings
- Avoid hitting them with lawn tools, bikes, or kids’ toys
- Keep the path between sensors clear
- Schedule a tune-up once a year to check sensor alignment and wiring
Need Help? We’re Just a Call Away
Whether your sensor lights are blinking, dim, or completely out, Four Seasons Garage Doors is here to help. We specialize in garage door diagnostics, safety sensor repair, and full system maintenance.
Call us today at 630-449-4600 to schedule service anywhere in Illinois.
