My rear drivers side brake light/turn signal is out.

Also it is a 5.7 liter z71(old body style)

check the ground for the tailight as well as the circuit board they go bad and are in thetailight. check your relay for the power door locks , it s in the underhood electrical center also if you have another fob, see ifit doesn it with theother fob as well.

I should of added that the taillight itself works, just the brake light and turn signal does not....are those still possibly the solutions? And would the relay cause the door locks to blow fuses?

the taillight problem could be a bad turn signal switch. you need to have a test light to see if you are getting powr to the light socket. if you are there is a good chance that the socket is bad or a ground. if you blew fuses you could have a wire shorting to gorund or a bad motor. check the wiring harness where the dooor closes as those can break there.

Do know what color wires control which light at the taillight?

it depends on whether you have old style or new style. New style has a blue and brown wire running to each tailight and it's been broken down in circuitry old style has brown yellow and green wires.blue is for stop and turn signals. yellow is for right side stop/turn i think and green for left or vice versa

Ok I fixed the brake light, last question....my drivers side windshield wiper went nuts...it appears the little brass like fighting is either loose or stripped(see pic below). Any ideas? Can it b tightened or does it need replaced...if so what parts?

Also is that fitting brass? Could it b spot welded as a temp fix?

youll have to replace the wiper arm.the locks sounds like bad door lock switch.if the turn signal doesnt work after installing the bulbs you will have to replace the flasher.