Mine shut down all the lights. When I replaced it, everything worked fine. I don't know if it carries a common ground or is connected some other way. Like I said, mine was a floor dimmer switch, so if yours in on the column, it may not have anything to do with it. I'm fighting through all sorts of electrical issues with mine right now and am finding a lot of stuff that is connected together, even though the wiring diagrams don't necessarily show it.