Sounds like the left hand brake switch has gone out. You can confirm it by pulling the left brake lever and looking to see if the brake lights come on. If they don't the switch is bad.
Part number for the switch is 57460-17C11. They run about $25. Here is a link to a fiche with the part on it. It is item 5. http://www.partshark.com/fiche_sect...gory=Scooters&make=SUZUKI&year=2003&fveh=7244
As you can see from the fiche it is only held on by a single screw. Takes about 5 minutes to change.
Part number for the switch is 57460-17C11. They run about $25. Here is a link to a fiche with the part on it. It is item 5. http://www.partshark.com/fiche_sect...gory=Scooters&make=SUZUKI&year=2003&fveh=7244
As you can see from the fiche it is only held on by a single screw. Takes about 5 minutes to change.