Lets see the left side of my lighting system doesn't work properly (exluding headlights).. the left brake light was hardly noticeable during the day so I bought a new bulb and it was still very dim. My turn signals work fine with my headlights off. As soon as my headlights go on my left turn signal well it used to not even work at all. Now it will blink very slowly and only blinks in the back. The front remains solid. And also when i'm not using my left turn signal the green light remains on in my dash.

Any idea on where to start?

 

look and make sure you are useing blub 1157 not 1156, in the front and rear