I discovered today at my rental house that the garage door safety sensors are not working. This is seemingly the opposite of the usual problem, in which an obstruction or misalignment of the sensors causes a door not to close.

In this case, both sensors show a green light. If the door is closing and I block the sensor beam, the door still closes normally. The lights on the sensors do not change when I block the beam.

This is an older opener, made in 1996, with a green programming button. I think the sensors worked correctly when tested as recently as four months ago.

I'm wondering where the problem is and how to test things to see if a part needs to be replaced. I can think of a couple of possibilities. First, the logic board could have a problem that causes it to simply ignore the sensors. That seems weird, though, after all these years of normal operation. Second -- and I don't know if this is even possible -- one or both sensors could have a fault that tells them to report a continuous beam across the garage opening even when the path is blocked. But why?

Has anyone even heard of this problem? There are zillions of articles on the internet about sensors preventing a door from closing, but I have found nothing about sensors not functioning.

 

First thing to try is to disconnect the sensors from the opener. See if it still closes. If it does.... you know it's an internal problem. If it doesn't.... you'll need to replace the sensor pair.

Pretty old unit.... we'd need a make and model to comment further on the safety system.

 

It's a Craftsman 139.53535SRT1.

 

Safety sensors are definitely required for that unit, I'd try disconnecting them first and see what happens. The part number for the sensor kit is 41A4373A and by searching can be found at many places.


Chamberlain/Sears manual..... chamberlain/files/tucmanuals/A1954M.PDF