Why would my garage opener light intermittently or when no motion is detected in the garage?

HVAC & Fireplace Bucket EXPERT July 31, 2008

You mentioned "motion" and "entering the garage" so I assume you have the motion detecting wall control and you mean the light no longer triggers when you walk into the garage passed the wall control.

While the safety sensors mounted on either side of the garage door itself work strictly by sensing something moving between them, the wall control works by noting changes in temperature. This is a better system for the wall control since there is only the one sensor on the wall itself to work with and mounting a second sensor would only allow it to work in the small area directly between the two.

But the tiny wall sensor has to be very sensitive to pick up the small temperature variation of someone walking passed. And, when temperatures change dramatically, that sensitivity can make it difficult to calculate the change properly so the effective range of the sensor is really between about 40 and 100 degrees Fahrenheit. As you get close to those upper or lower limits the sensor has a harder time processing temperature changes.

I am guessing that you are in a region of the country where winter weather recently caused the temperatures to drop. Since the sensor has a hard time processing temperature in extreme cold, the radical temperature changes of a winter night can fool the wall sensor into turning the lights on, and keeping them on, even though no one is walking passed the wall control at all. You can check if this is the case by simply turning off the motion sensor, there is a small switch on the side of the wall control itself, and seeing if your lights still come on at night. If not, then you are simply dealing with too much cold for the motion sensor and you may need to leave it turned off, at least at night, until temperatures come back up somewhat.

None of this will affect the safety sensors mounted on either side of the garage door itself. That important safety feature will still operate as normal since they do not rely on heat but on something blocking the line-of-sight between the two sensors. And, since those sensors control the Light Feature it will also continue to work normally. So if you find that walking through the safety sensors of the garage door itself does not turn on the light then that Light Feature might be turned off altogether. Your Owner's Manual will have information on how to turn the Light Feature on and how to adjust the length of time the lights will remain on before automatically turning off.