1999 sable blinker lights

i have a question about my 99 sable.my son hit a deer and now the front blinkers dont work.The bulbs are good, parking lights work, four ways flash fine. when you turn the when you turn the lights on the blinker light come on in the dash. the only thing i can think of is the distrubution box above the fans, how can i find out if its bad?