Your ect (engine coolant temp) sensor comes off the engine to the ecu. Fan relay is controlled by the ecu. I would run 12v (through your switch) to the black/blue stripe wire coming off of the fan relay.
Check out www.MOTYDesign.com Owner is a great guy with some great products. Super light weight LiFePo4 batteryies for the bike and quality tire warmers. (both digital and single temp)
Laid the bike at the end of the 2010 riding season. Repaired all the damage and rode it last year. This year I wanted to give it a face lift. Note: all photos shot with an iPhone 4..... From this: To this: