turn signal assembly in the steering column . get someone to watch for you while you put your foot on the brake and then wiggle the turn signal lever. see if your lights come on, or back up to a wall or something to see reflection. Do this with the key in the off position. I just replaced one in my buddies '77. He only had one brake light that would work, but hazards, and turn signal worked. problem went away. Hope this helps !!