Garage door opener safety sensor problem [DIY]

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I had a problem today with my garage door opener. When I pressed the button to close it was not doing so and flashing the light bulbs instead.

The first thing I thought was something was blocking the safety sensors. Checked and nothing was blocking them. Next thing I though was that they were dirty. Cleaned them and nothing happened. Third thing I thought was that they were misaligned. I proceeded to realign them and even put them at a distance of 12 inches and nothing happened.

With those tests performed, I went ahead and researched on the web for possible issues.

I found this article explaining about the flashing LED & count for the led above the learning button:

Number of Flashes Problem Auto Reset Manual Reset
1 Photo-Cell totally misaligned or Photo-Cell wire open X
2 Photo-Cell wire shorted or the wire is reversed on the terminals X
3 Wall button (panel) wire is shorted in wall or attic X
4 Photo-Cell sensor sightly misaligned (dim or flashing LED on sensor) X
5 Possible RPM sensor failure or motor overheated, unplug opener to reset unit X
6 Motor circuit failure, replace main logic board X
Rapid Flashing This is not a problem but just an indicated that the opener is receiving a signal but it will not respond to an unauthorized code

Mine was flashing once, but one of the sensors was flashing intermittently. Every now and then it will be flashing 4 times too. So this test was inconsistent.

I searched again and found this article that pointed out:

11. Door does not close, light on garage door opener flashing:

  • Check The Protector System. Both sensors must be aligned or aimed across the door opening without any beam obstruction. Remove any obstruction or align both sensors.
  • Check for spider webs and/or dirty lenses. Wipe clean.
  • Make sure both LED lights are solid on each sensor housing.
  • Check safety sensor wiring and connections to the power head unit. Repair as necessary.
  • Check for diagnostic flashing code “1”. Located at the power head unit.
  • Try replacing safety sensors. Retest.

I have opted for the last recourse. To replace the safety sensors and retest.

Fortunately amazon has them in stock and taking advantage of amazon prime I should receive them in 2 days.

Will post an update once replaced. Wish me good luck.

Liftmaster 41A5034 Garage Door Opener Safety Beam Kit

Liftmaster 41A5034 Garage Door Opener Safety Beam Kit

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  • Hello, This post is very creative and very useful.This post provides a lot of informations to remove the problems which could occur with our garage doors.This is really very desirable according to the situation and demand of customer. Thanks for usable news

  • Spooderoo7

    Hey I have the same problem and have performed the same test you have. My led flashes four times. Did the phoTrevorto eye kit work? Thanks my email is


    • I changed the sensors but they were not the issue. You need to check cabling
      and ensure there are no cuts. In my cause a piece of cable connecting one of
      the sensors wore out; it was bent multiple times.

      Good luck.