Depends on what amperage you need but the heated grips and seat are switch 12 volt wires......

 

The only reason you would use a separate relay is to not put an accessory that draws a lot of amps on the bikes electrical system. If your using a separate relay you would want to run the main load + and - leads directly to the battery (it would be a good idea to tie in a fuseable link close to the battery) and the relay coil lead to just about any switched power wire since it draws very little amperage to operate the relay. If your not using the factory heated grip connectors in the fairing or the heated seat connector either of those would be a good source of power for your lights and you don't need a separate relay.

 

Were you going to use a separate switch or did you want them to come on with the high beams? Lou8700 has it right, the relay takes minimal current to close.

 

If you look you already have wires under fairing for driving lights. They will be caped off by headlight wires.
You would have to order switch from dealer to go in that blank switch hole you have on outer fairing