I have a problem with my 1978 chevy pickup tail light. It is the left tail light that doesnt work when I press and the brake and the signal. And the light bulb is good. but when i put on my parking lights it lights up but doesnt signal or brake at all. Also i checked and i have power to the light socket. Any help?

On an #1157 bulb there are two different filaments. One is for parking lights.
The other is brake/turn signal. One can burn out and not the other. Change
your #1157 bulb. If for some reason it isn't the bulb, check into the turn signal "switch" on the column. Good luck!

The cheapest thing to do is change any and all bulbs in that tail light. if 1 is bad it can effect all of them. hopefully you don't have a short somewhere. but i would try the bulbs first, they're only a couple dollars and usually the problem. gl