hi kefty,one of my first jobs on the tenere was heated grips and cigarette lighter stlyle connector for sat nav / phone charger etc

the panel facing you [rear of the lamps]needs removed,two allen headed bolts,gently pull cover towards you.a loose cable with two connectors positive/orange and earth/black-white you could just cut off and join in or try and get the proper joiner from yamaha[i had a connector from a toyota that was close enough so was ok]. as captmoto said an fuse should be incorporated,that line supplies the side lights and has a 10 amp fuse so use something lower.the power is controlled by the ignition so flat batterys should not happen..

the cigarette connector is from maplins,cable tied to the clutch cable but i have seen a far neater fitment, using a halfords connector a hole was drilled into the curved 'cheeks' that are left and right of the lamps [should have taken a picture]and a nice plush fitting was made, you would think yamaha had designed it from the start! [i think peatbog did it]

a pic of mine

hope this helps