I have a number of 12v lights in the kitchen, under wall cupboards, in a dresser and in the ceiling. The ceiling lights give me no problem but some of the others do. The lights work somertimes do not work which is usually remedied by tweaking the wiring or more usaully removing the glass and moving the bulbs. I have replaced some with a differnt type but the problem remains. The common element between both types is the bulbs which have two thin prongs. Any ideas?