i'm betting that more often than not all they have to do is plug it into a wiring harness that was installed correctly. Which probably completes the whole process. Then its sent back.I think ur asking what refurbished means. Its when a product is sent back to the company that made it, then they replace all the bad parts with brand new ones and resell it in complete working order. Sometimes it might be as small as them replacing a missing button
or insert a CD instead of a Floppy. something of the sort.
you guys know what floppys are right?