No left turn signal or brake light

[1978sierra]

Hey Guys,

Was driving home yesterday when my left turn signal stopped working. When I engage it the green arrow lights up on the dash but it does not blink, no signal on the left side front or back.

When I put on my hazards the green arrow blinks and the front left functions properly, the back left does nothing.

I also don't have brake light on the back left, but I do have running light and reverse.

Any help would be greatly appreciated.

Cheers,

[MountainGoat1966]

Check the bulbs (all four corners of the truck) they can look good but still have a bad filament.
Also, clean and tighten the connectors and bolts on all the ground wires.
Sometimes, a socket will fail.
I had a socket where one of the internal contacts just disappeared and the light would not work correctly.
To this day, I still don't know where that contact strip went .......
That will fix 99.999% of the issues you have when it happens.