darn brake lights

:flash: i have a 93 chevy cavalier, that runs great (sometimes) but i have had a problem and it came back once again, all the lights work except for the brake lights and 4 way flashers, the left blinker blinks erratically, i have changed the bulbs and checked the fuse box only to find that on fuses were blown, what else should i check before spending $70 \ hr to let someone stare at it for 3 hours then tell me they need more time?