Well, there is one set that is not turning on, and I guess that's the one that are not installed here in US; however, I figured that another set that when I break should go on, only one of them turns on. I took the lamp and the base of it and put in the other slot below it and it turned on. So, it's not the lamp or its base which is the cap that lamp goes in it. Now, I am wondering if there is a sensor or something that is burned out.