I know they are both good, because the one side works better than the other, and usually lights up the lightbulb, so I just exchanged them and the other u-light works as well. Where would the starters be? This seems like a simply mechanism. The wires come from the switch in the wall into the ballast, which then go to four pieces that house the nipples of the bulbs. Which is why it's frustrating, because it seems that it can only be the bulbs or ballast, both of which either have been replaced or work.