Calling electric gurus, help!

If the switch does have all these mystery wires, start by activating the hazard switch, which hooks the "most wires to the most wires." Then you can quickly find a few wires that are connected. Then go through and check them all and bunch that amount of wires over to side, you know they are all connected.

If worst comes to worst pull the wheel. This should enable you to get in there and separate the horn circuit, and probe the wire connections on the TS switch so you know you are on the right track