There should be a pigtail coming out of the SmartCraft Speedo connector; similarly there is a pigtail comming out of the connector on your sonar (I think it is on the GPS cable). Cant remember the colors, except one of the wires is bare. If speedo does not work, reverse them. But first, you have to dig into the bowels of the HB menu and enable the NEMA output as previously stated.jet