Is there still a plug on the mic, and do you know what radio the original wiring is for? If so, you can make yourself a 'cheat sheet' by writing down what color wire is connected to what pin - i.e. pin 1 shield, pin 2 audio/white, pin 3 transmit/red, pin 4 receive/black. Then transfer that color code over to the appropriate pins on the plug for the Galaxy.