lights & dash lights

I have a 2000 firebird and I have this problem with the headlights and insturment lights slightly flicker when I press the brake pedal this only happens with the lights on.

I have checked all the ground connections,
has anyone had this problem or got any ideas on a fix.

hey bud! I cant relate but i will tell you this as i was looking through my manual the other day i saw a fuse claimed to control that. Im not sure of anything but check your manual> go to the index look for fuses and circuit breakers and go from there.
Hope that was of some help.