If you look between the right brake lever on the bars and the mount, you'll see a tiny switch in there that contacts the handle when you release the handle to break the circuit that light's the brake light. If the handles were removed and reinstalled, it's a good chance that the brake light switch was broken off in the process if it was not done right. I've also seen them where they needed a tiny touch of WD40 when they were sticking too.

This link will give you some understanding of the disassembly of the switch housings... HERE

This is what you have to do when you remove the brake lever housing so you don't damage the switch.


It's not hard, time consuming is more like it. You should first check to see if it is just sticking, otherwise you have to disasemble the switch housing and remove the screw that holds the switch in place and replace it with the new switch. You have to cut the old wires and connect the new switch wires and solder and shrink wrap them nice so they all fit back in place good, then reassemble the switch housings being very carefull not to pinch any wires. Re assemble them by hand into the proper positions like a finished job with all the seams lined up and THEN put the screws in and tighten them. This way you can't clamp down on a wire that is in the wrong place or not exactly in position. It can be equated to putting 7 LBS of you know what into a 5 LB bag Not a hard job at all, just take your time and you'll be fine. Remember to space the lever like the picture above when you reassemble it or you'll be doing it over again and while you're at it, apply a dab of grease to the inside of the mount where the brake lever rubs too.