Is your GPS receiver the same as the picture? The picture shows the GPS antenna puck on the right. Then the wire exits the puck to the left and becomes a heavier wire going straight up. At the top of that wire is the plug which would go into your unit or the wye cable which allows the GPS and other accessories to plug into the unit. The wires you are talking about which go into the box in the picture, the red, black, white, are for sending the GPS signal to a emergency radio, anchor alert or to another unit that may need GPS signals. If you have the 998c si only, those wires are not needed. Now if you don't have the plug depicted at the top of the heavy wire that runs to the top of the picture, then you must not have the correct receiver or somehow it got thru quality control with no plug. So you will need to contact H/B and get a replacement. PS Those red, black, white, green wires, are just duplicates of what is inside the main cable. That way if you need GPS signal elsewhere, you don't have to cut or splice into the h/b harness.