I really need help here, ive been trying o figure this out forever, for some reason my left signal will always be on when i turn my lights on, like it doesnt flash but its always on, on the dash and the actual signal. Ive replaced the bulbs and its fixed it temporarily, but then it comes back! i even replaced both signal sockets, it was gone for a bit, but comes back! then i noticed the hotter it was outside, itd be gone, the colder and damper, is back, i really wwant this fixed its so annoying, someone please help me

 

Look under the rear of the truck for a trailer light harness .Look it over real good as many light problems start there.

 

Have you checked all of the grounds, headlights too.
Redo all the grounding in the headlight area.

Sometimes when a ground goes back in one component, that component will attempt to locate and use another components ground via the actual component causing the second component to activate a little.

“Path of Least Resistance”