1999 gmc jimmy brake lights
 

alright, so my left brake light on my 99 jimmy 2d 4x4 does not work. i push the pedal, the 3rd light and right light come on, but the left does not. left blinker works fine. i bought new bulbs and put them in, i bought a new brake light switch and put it in. still not fixed. i just watched in the reflection on another vehicles tailgate behind me as i played around with my brakes and my blinker and out of nowhere my left brake light was working as if nothing was wrong. then a while later after using my blinker and hazard lights etc the left brake light decided it didnt want to work anymore. so it sounds like the fuse is fine, the switch is fine, the bulbs are fine, what else is there to check? going to do a wire and socket test tomorrow but thats the only other idea i have, anyone have similar problems before that they have found solutions to that i may be overlooking?