If you have the box and the control panel out so you can look at them a good long look should tell you which control goes to which system. One will operate a door to open and shut for the defroster. One will open the door to allow ouside air to blow by the core as it brings heat into the pass comp. One will do something else that I can't think of right now but if you look at where the cable hooks up to the box, and which operation it does, it should be pretty apparent what cable goes where. It might be a little tougher laying on your back under the dash but not impossible.
