Question about Garden

1 Answer

How do you troubleshoot optical sensors on a liftmaster garage door opener.

Posted by on

  • spinnerx2 May 09, 2010

    Are the sensors normally a closed or open circuit during normal state?

  • spinnerx2 May 09, 2010

    That will help me determine if the sensors are bad.
    Have a good weekend, and Mother's Day.




1 Answer

  • Level 3:

    An expert who has achieved level 3 by getting 1000 points


    An expert that got 20 achievements.


    An expert that got 10 achievements.


    An expert that got 5 achievements.

  • Master
  • 8,197 Answers

Look at both sensors, located near the floor on either side of the garage door. If both sensors are steadily lit, there is no obstruction. If one is flickering, it means the two sensors are misaligned or something is obstructing their path. Remove any leaves, dirt, debris or objects around or in the path of the sensors to see if that fixes the problem. Next try tightening up the wing nuts that fasten the sensors to the wall to bring the sensors back into realignment.

If either light is out, check the sensor wires attached to the white and black terminals on the overhead motor unit panel. Make sure they are properly connected and that a short is not occurring. If this does not solve the problem, consider calling a garage door specialist.

Posted on May 09, 2010

  • Jyackle5
    Jyackle5 May 09, 2010

    The sensors are in the closed state when they are working correctly.



1 Suggested Answer

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017


Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Garage door sensor blinks continuously - door wont close

It is getting a signal, but the wrong code. Call the dealer for your garage door and ask for a solution.

Jul 28, 2013 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

I have liftmaster professional garage door opener. it opens ok but does not close with remote and light keeps flashing on garage door opener. I checked both sensors and seems like the sending sensor light...

If your sensors are not pointed at one another the light on one of them will go out. Tweak them a bit. If you cannot get the light to come on then your sensors are bad.

Oct 25, 2010 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Craftsman LiftMaster Chamberlain Garage Door Opener Wireless Keypad Model 976LM Security+: Can I bypass the sensors on my garage door opener?...

You cannot bypass the sensors but you can try reversing their position so that the sun isn't hitting the receiving unit. You can also move them back from the door or use something like the tube inside a roll of toilet tissue to shade the lens.

May 18, 2010 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Craftsman LiftMaster Chamberlain Garage Door Opener Wireless Keypad Model 976LM Security+: i'm reinstalling my garage door opener because the...

Terminal #1 - White wire with red tracer from wall control

Terminal #2 - Three solid white wires. One from wall control and one from each of the door sensors.

Terminal #3 - Two white wires with black tracer from the door sensors.

May 17, 2010 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Cant get any of the lights on the optical saftey for the garage door opener

Make sure it is hooked up properly. The wire with the black stripe go to terminal 3 and the solid white wire goes to terminal 2. There is always the possibility that you need new sensors.

Nov 11, 2009 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Liftmaster 41A5389 won't shut

it has to be aligned with its mating optical sensor on the other side of the door. try adjusting it until you get a green light.

Aug 22, 2009 | Sears Craftsman LiftMaster Chamberlain...

2 Answers

I have Chamberlain LiftMaster 1255R garage door opener. The electric eye does not lit and the opener unit flashes 5 times and then off. Do you know what the problem may be?

My garagedoor opener is not working.
I open the box and found the plastic gear worn out.
I have Liftmaster 1255R.
Do I need to replace the whole box or replace the worn gears?

Jul 08, 2009 | Sears Craftsman LiftMaster Chamberlain...

1 Answer

Garage door sensors

#2 and 3 on my opener. #1 and 2 are atteched to the wall button. So # 2 has both attached. Hope that helps.

Aug 20, 2008 | Sears Craftsman LiftMaster Chamberlain...

Not finding what you are looking for?
Garden Logo

Related Topics:

50 people viewed this question

Ask a Question

Usually answered in minutes!

Top Garden Experts

Dennis Key
Dennis Key

Level 3 Expert

2478 Answers


Level 3 Expert

666 Answers

john h

Level 3 Expert

13685 Answers

Are you a Garden Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides