I just spent Saturday fixing my grips on my '07 800R. I had a weird short every time I powered the heaters on high (not on low), and it wanted to cut out the engine. Well, both grips had the wires almost pulled out and the right one was shorting out.
Check the leads on the connectors for the right resistance: the wires you need to chase are orange, orange, and black; these wires create 2 circuits with 15 ohms and 8 ohms - the higher resistance is for the hotter position, etc. The left hand is a no brainer, the leads on the right hand connector are relative simple as well (upper corner - 3 leads). If your resistances check, it might be your switch.
I had to repair my hand grips and ended cutting-peeling the rubber grip around the wires and soldering them back to the terminals. I verified the resistances of the leads coming out of the connector and used SHOE GOO to seal the wires again. For good measure I wrapped electrical tape around it and beefed up the wire exit. The wires are only crimped to the solder leads so when you do this operation I suggest to solder on top and do not try to open the crimps; it tends to separate the crimps from the heater traces. If you rotate the grip skyward, and peel back about 1/2" of the grip (only the raised area where the wires exit) you will see 3 crimps: power (15 ohm circuit), power (8 ohm circuit), and ground (for the black wire black).
Good luck chasing it.
Z
