Occasionally when I use the turn signal it buzzes, is this a bad Relay?

The turn signal flasher relay may be going out. A local shop can test to verify that its the relay. The part generally runs $30-$50 with labor /diagnostics at $100-$150

How often does it 'act up'? My wifes '99 Explorer did that same thing briefly (like for a month 1 or 2 times a day -say 1 in 20 times using the signal), told her to just be 'more deliberate' with hitting the lever and , not really sure , but it's been almost 2 years now and no further issues with that. MY personal thought , I think the switch is worn inside and contacts were getting 'hot-spots' causing high resistance.