68 mustang lights don't work
My brother has a 68 mustang and when the headlights are off the brake lights work. When the headlights are on he has no running lights or brake lights. About every 5-7 seconds he hears a clicking noise that sounds like it is under the dash and the headlights flicker. Can anyone help lead me in the right direction on fixing this. He already changed the light switch and that didn't help.