Sigur

The SWI has one wire (white) that takes information from your steering wheel wires. Since the Z has two wires that give a momentary signal to the SWI the resistors are used to that the SWI can tell which wire is active when they are both tied to the white signal wire. All the resistors have a gold band that you put to the right i think, and three other bands of color that you read from right to left. If you dont want to solder you can just put one end of all the resisters crimped into a butt connector and the white SWI wire, and connect the other end of each resister individually to the proper steering wheel wire with a butt connector. It's basicly just a 12V signal saying the button is pushed like a amp turn on wire, there is no reason to solder if you don't want to. Since the wiring harness usually doesn't have wires for the steering wheel wires you can rob unused wires from the harness (rear speaker wires for base people etc) and move them to the steering wheel pin location to avoid cutting the factory wiring at all.

I haven't confirmed this, but I don't think it even matters if you use the right resistor on the right wire. As long as the SWI can tell the difference between the two you program the buttons after it's all hooked up anyways.