The 105/115 switch [S-25/6] is on top of engine . The wire you want to ground for high fan activation is br/gn. That will complete the circuit from K9 high speed aux. fan relay , which by-passes the dropping resistor and feed fan motor full 12v.

For low fan, you jumper br/bu and br at reciever/drier switch [ S/32 } for low fan relay K-10 preresistor circuit. This feed uses the resistor in series to drop the feed voltage to fan ,resulting in low fan mode [ a/c only]