IN need to replace the PCM on my 2004 Ford Sport Trac where is it located

Why oh why do you feel like you need to replace your PCM? This most often doesn't resolve anything. What is happening that you think you need to replace your PCM? You'll need a diagnostic tool to "inhale" the old PCM data so the new one can be programmed properly. You'll also need a diagnostic tool to program the PATS system. Perhaps rethink trying to do this. Share what is going on with your vehicle.