i did some googling and that's what i came up with from some other grand prix forums. supposedly a safety measure built in with the 3rd brake light. and if fluid is low it was something about the pedal would sag and disengage CC like you were pressing the pedal. made sense in my head. there were some other ones like speed sensor that i didnt check.

i'll just have to suck it up and get it looked at this weekend. suck.