If you look at the main bolt holding the brake assembly together , directly below that you can see a bent bit of metal and its touching a piece of metal protruding from the frame....I think that's it, I might be wrong tho'..Not really looked for it mate....Tosh
The rear brake switch is very difficult to see, as it probably full road crap and oil from the chain. I am reading from my Haynes manual ....
On GS, Dakar and CS models the rear brake light switch is mounted on the inside of the frame above the brake pedal. (see illustration)
So there is one.
You need look slightly up on the right just above the brake pedal pivot and then behind a flat spot of the frame. As a guide the chain returns to the rear sprocket at that point on the frame. It is black on the photo and about 3-4mm thick.
I love it when im right. Ive just gone into a bloody freezing garage to take these photo's for you...
Ive pulled down the rear foot brake to take one of the photo's and realised that the rear tyre or disc isnt on the bike so the rear caliper will have to be prized open to fit the wheel back on...Ohh joy..What a ball ache, Anyway hope this helps.....
You can see the wire going down to the switch next to the scotoiler tube...
You can see the brown strip of metal, That IS the switch arm...
This is the photo that has closed my rear pads in the caliper..
As you can see very clearly the brake switch arm and the foot brake lug..