The extra wires are so if you manually lock/unlock that door it will do the rest. If your having trouble finding a genuine actuator I'll tell you a trick.
We bought a np Pajero and a couple of the doors weren't locking/ unlocking with the key in drivers door. I rang around a few wreckers for actuators and no one local had. So I went down to supercheap, bought one of those cheap af central locking kits, not even the one with the remote ( so like $39 or some shit). Then I just removed the existing actuator and modified the bracket to fit the supercheap parts, just have to test as you go to make sure your wiring the polarity right otherwise the door might lock when you press unlock. So the 3 wire actuators worked for all the doors besides the drivers. Once I'd done that I brand a remote home from work and programmes it in and somehow, even though the drivers door worked with the key to lock/unlock the rest it wouldn't lock/unlock with the remote. So I pulled that door apart and dos the same thing but used the 5 wire actuator instead. Works 100% every time and now if they break again I have a couple spare 3 wire units and if I need another drivers side just go buy a whole kit instead of the 200-250 or some shit mitsu wanted lol.
Hope this helps!