So my brake lights work without my headlights on but with the headlights on if I hit the break it kills the driver side tail light and brake light also with the headlights on if I turn the left blinker on the left tag light blinks. I’ve checked the fuses and the grounds and junction blocks. It’s only the drivers side. Everything else works. It had a 2.2 in it in the original owner took a 4.3 out of a 2004 blazer and put in it don’t know if that has anything to do with it. It has me baffled I don’t know

 

Check the wiring and sockets at both rear light positions. Sounds like a short somewhere and possible bad sockets.

 

I’ve already changed the socket also