you shouldn't need to remove the whole radio dash for this, i think you would be fine with just removing the radio or even using a coat hanger to pull the wire though to the other side, but i'll explain all 3 ways:
1) Coathanger - straighten out a coat hanger and open the glovebox and on the left side towards the front will be a hole where you can push the coathanger through to the otherside (use a flashlight to see where your going, you should be able to put it above or behind the radio and to the otherside), it should come out on the left side near the steering wheel.
2) Remove the radio - eitehr go to best buy, walmart, etc etc and buy ford radio keys for about $2 or $3, put them in the whole on the sides of the radio,pull towards the outsides and pull out, or make your own set of keys with a coat hanger, straighten it out and cut two equal peices about 5" or so long and use needle nose pliers to bend a very small loop at the ends and smash the loops down. It's har dto explain but these ends let the hanger catch the radio clips to allow the radio to come out.
3) do #2 but take the 4 screws out (once radio is out you can't miss them) and then pull it straight out, this will remove the radio from the 4 clips hodling it on.
Let me know if you dind't understand what i said, good luck.
- Scott