2004 Ford Expedition Premium Sound Wiring

"Does anyone know what exactly pin numbers 14, 15, & 20 mean?" Pin 14: Vehicle Speed Sensor - Gray/Black: This wire is used for the speed sensitive volume on the OEM radio. If down the line you add a navigation system that has a hookup for VSS, this is the wire you want. For a normal radio, not required. Pin 15: Voltage Supplied In Start: I'm not real sure what this does maybe someone else knows. Possibly like a positive mute wire since I think the audio cuts out when starting? Either way it's not required if installing an aftermarket radio. Pin 20: Parking Aid, mute signal: If you were installing a hands free kit or something, a negative to this wire will mute the speakers in the vehicle. Technically it only attenuates them quite a bit, not completely stop the sound. It should mute the speakers in the vehicle if you turn on your parking aid feature in the vehicle, if equipped. For a normal radio install, not required. If you want to turn on an external amp, you could either run the remote lead on the amp to the pink wire in pin 2, or to the blue wire on the aftermarket radio. None of those pins listed are going to help you. Mike

Thanks Mike.  Great help.