Mehrcatode in Technical Discussion Posted October 24, 2011 · Report reply I replaced the long block and found free wires with marks Mercathode. Where do they have to be connected? Hi, Here is a link to a site which discusses the Mercathode system http://www.mercstuff.com/mercathodekit.htm There are several anodes which have been developed over years but the Blue or black controller has not changed very much. You need to look for the little blue or black plastic box mounted somewhere on your top of your motor and connect it up as shown in the diagrams in the above link I cannot tell the colour of the cables in your wiring harness. You only have 3 - the controller has 4 terminals. It would safe to assume Orange = terminal marked "A" (from one side of the anode) Brown = terminal marked "R" (from other side of anode) Red/Purple = terminal marked "+" = your battery "+" post. This should be permantly connected to your battery with an inline fuse. Do not run from any switched circuit. Black = terminal marked "-" = your battery negative "-" post You will need to leave your battery chager running to keep your batteries topped up.