The yellow light flashing is the indicator for your right and left turn signals. If it is flashing and your tunr signals are not, then you probably have a wiring problem. its a matter of routing usually. the front and rear signals have similiar colours, as does the horn. Its a problem you need the schemativ for, and then some wire labels and a continuity tester so you are sure you are dealing with the same wire at both the front of the bike and the areas where the connectors are and also in the headlight bucket. its just a tedious job.