I have a Hampton Bay model ac-552al. The black box that connects to the pull chain switch has shorted. Where can I find a replacement? There are no numbers on the box, just a color coded wire diagram. It has a grey wire coming from pull switch to one end of box, another grey wire is on that end too. On the other end is a brown wire coming from pull and another brown wire and a red wire. Can anyone tell me what this part is called, and where I can purchase a replacement part. Thanks