For some reason, on my 71, :confused: when i turn my headlights on, the tail lights work fine, but if i turn my turn signal on or hit the brakes, theres nothin. Its all the same light bulb. I checked the contacts on the plug going into the brake light actuator or whatever you call it. How do i fix this?

I am having the same problem on my '70. The suggestions have centered on another ground from the battery (neg) pigtail to the inner fender.(see my post below). I have not had time to try it yet but I sure would be interested if you figure it out. Thanks, Skip

It's the same light bulb but the bulb contains two filaments. One for the brake/signals and one for the tail lights. Try:
Remove one of the bulbs.
Have someone step on the bake pedal.
Measure, with a meter or test light, the green (or yellow) wire to a good clean frame ground. You should have 12 volts from green to chassis ground as someone steps on the brakes. See if that's present.

Brake lights and turn signal circuits both go thru the turn light switch. Suspect the problem is with the contacts inside the turn signal switch.

try turning the blinker on and wiggle the hazzard light button on the column.I drove around pushing that button foward to make the blinkers work until I had a chance to replace the turn assy behind the steering wheel.Now I can drink coffee and drive.MERRY CHRISTMAS

Thanks guys, keep the suggestions coming, i am going to try every single one of these troubleshooting clues tomorrow after work. Thanks again and Happy Holidays

Thanks guys, both brakes and blinkers work now. The two prong light bulbs were the wrong part # from what the computer at the store says. that might have been why the brake/signal prong burnt out but the tail light prong didnt. I replaced the burnt bulbs with the correct part # and all ends well. Thanks. I tried the volt meter while the wife tried the brakes. Worked great, thanks