ac & wiring prob.

I have a 2002 pontiac sunfire that has been blowing the erls and inst. cluster fuses. i couldnt figure it out untill finally i found a black and white wire coming out of the bcm melted. i traced the wire under the dash untill it went into four other black and white wires. i dont even know what these wires are or where they come from, because in the haynes book wiring diagram it doesnt even show a bcm, well it does show one but has only 4 wires and the one in my car has about 50 in three different connectors. it all messes up when you turn on the a/c so i unplugged the blower moter and it doesnt mess up, anyone have any ideas?