Is it just the indicator on the dash that quit working or have the turn signals also quit working. There are a a variety of different things that could cause this.
If its just the indicator on the dash then you might have some issues with the multifunction switch wiring connector. Sometimes the wires work themselves loose and things like this can be an indicator of that.
If the turn signals have quit working all together then it could be anything from bad flasher, bad multifunction switch, bad multifunction switch connector.