Depends on which radio and MFD you have. On mine (see below), only one plug (middle top) from the MFD was needed for AC. The radio had two go into the supplied harness adapter, one for power (bottom right) and one for steering wheel controls (bottom middle). Small plug on radio goes to rear console. Small plug on MFD goes to stock reverse camera, I think. The main plug that supplies power to MFD didn't go to any connector on my adapter harness. Your extra adapter harness plug didn't connect to anything on mine either.