there is a small green top on the back of a b16, it has two prongs sticking out of it that are for connecting to two wires. it is about the size of a quarter in diamater and the prongs face the firewall when the motor is installed. it is on the back of the head or block...

anyway, there are two wires, a black and a yellow...and the quarter sized fiberglass item is not marked for positive and negative. does it matter which wire we plug into which prong? what is this thing im talking about, anyone know?