98z28camaro

hi i havent had this car all that long and i just relaized that my right turnsignal while driving appears to be working fine (inside and out) and my left does not work at all. in fact it seems to blink erradicaly and "flickers" my dash lights. my hazards or 4 way flashers also do not work as well as my brake lights. the brake ligths at nigth come on but do not get brighter when the brakes are applied. i checked and replaced the bulbs for the front turn signals and the rear brake light bulbs all are good. i also replaced the two front turn signal housings back to the factory orange or amber ones because the ones on the car were clear and one was cracked. i also noticed that the previous owner or some one had wired the two pig tails leading to the front turnsignals on to accomodate the clear lamps. i have new stock pigtail ends which i plan to change back to normal along with the new stcok turn signals. i am terrible with electrical issues and they tend to drive me crazy. i justw nat to knwo where to start looking and how to fix these problems. so any help would be awesome.. thanks..