I will bet you $20 I know the problem. I had a problem just like yours last year. You have to take a flash light and look under the cooling line that does through the break system and just below it you will see the brake switch. Its a peice that screws into the system with wires for the tail lights/brak light leading from it. Watch it closely and also listen. Start to pump the break lever and watch for tiny airbubbles/fluid comming from it. Watch the connection prongs where they come out of the switch and you should see the fluid come from there. Tell me what you find.