Lock on to a harvester with the hacking gun, when in the hacking menu just type in this order then press enter.

cd RFID
run setmaster
up
cd control
run activate

example1: X:\System_harvester_5090> cd rfid

example2: X:\System_harvester_5090\RFID> run setmaster


From here you can control the harvester by pressing I and going to ID then click the harvester and pick what you want it to do.(I found deactivating it before chosing what you want it to gather then activaing it works) If you click retuen here then that is where the box of wood(Iron/rubble) will be dropped. (If you have more then one make sure to set diffrent spot so it doesn't drop the box on your head and kill you)

Thanks to a bro who spent ages teaching me to hack in this game and making life in it a lot better.