I've got one of those plug-in electrical connector thingies that I just an't get open. There was an orange latch piece on it that threaded between teeth. I've slid that piece out and now the teeth appear to be free to move, but the thing won't open and doesn't feel like it is giving at all. Three sides of both halves of the connector appear sheer, and I've tried inserting a screwdriver blade down the fourth and twisting while I pull, but still no luck. What other fasteners besides the teeth do they use to keep these things closed?