yeah it's more or less like a pulley and some strings i think. shouldn't be too hard to replace, and i wouldn't even expect a junkyard to try and charge much for it, unless you were trying to buy the whole door hehe.

i replaced part of one on my brother's old s13. it's kinda a pain if you haven't done it, but most of it is just getting your hands in there. let me know if you need helps.