Turn signal issues

[88MJXLS]

I was driving yesterday when I realized that my left turn signal wasn't working, no matter how many times or how long I left it on, it just wouldn't light up (front or back) It did this before, but just occasionally at night with my lights on, now it happens day or night, without fail. My right turn signals work just fine, any ideas?

 

thanks guys

[Mongo]

Front turn signal socket. My 87's socket eventually rusted out where the bulb contacts are supposed to be, snipped off the wires and installed a $5 GM replacement socket from the Help section of the auto parts store. I had to both of them eventually since the long copper piece on the side of the socket is what left the building. Check that if your internal dash lamp turn indicator is on when the lights are on.