My standard series 3 heater has a coil thingy riveted to the heater radiator. I've seen them on heater blower as well. Can someone explain what it's for and how it wires up? I am trying to complete a refurb of the system. I've got two live wires one to the heater motor the other to this coil? What attaches to the other end of the coil? The blower motor is earthed to the cowling. Thanks