Battery draining fast

Purple is in fact temp sender. That year model alternator should be a round back casting and have only 1 field terminal connection in fact a green wire. All too often the charging system is upgraded to square back isolated field with solid state regulator which would have a second field terminal and additional blue wire.
If nothing has been altered/upgraded I cant say what a second green wire might have been for. If the horn relay is right out in front of the alternator on the radiator support a wire would jump from alternator to there but it would be a short wire and probably black instead of green.
Most importantly undo what you did before you screw up something more seriously.