Start with te easiest and pop both bulbs from the left signals. If you don't have a shorted bulb, check the wiring over carecully, especially where it passes through the signal light and headlight housings. Last thing to check, undo the switch housing and see if the fuse still blows when you hold the housing away from the handlebars. If not, the switch may have a short or the wires may be pinched where they go into the switch housing.
