indicator flashing

hi to everyone.... recently i notice that when i activate my indicators they flash really fast when the engine is on running ,and they flash normaling when the engine is off.
what could it be?

i recently came back from my holiday in Croatia. the bike run very well all the way but on the way back the battery went completely flat. Braken installed a gps nav. system ( tom tom rider) before i left for holiday and i belive it was the cause for the battery to go flat. . after i came back i booked the bike to bracken for checking the fault. He told me that everything is fine, he recharge the battery, charge me 35 pounds and told me not to worry. Now after only one week the indicator start flashing really fast and yesterday morning the battery was flat again! i do have the original allarm installed on the bike but it never drain the battery so much even after 3 weeks without using the bike. The problem is that dealers never want to do any work on the bike under warranty. my duke is only one year old and i shouldn t pay anything..... anyway on the 12 i will go to the Island of Man with a friend of mine (aprilia tuono) and i really want to fix this problem before i go...
Thank Dr F. for the advice.......