GOt a 94 K1500 4x4 pickup with ext cab and a whole bunch of custom crap that previous owner did and is now probably causing the problems. The problem is whenever I Hit the brakes, the corner lights, external auxiliary lights, dash lights, brake lights, license plate light, and buzzer come on. The reverse lights dont come on at all at anytime(might be reverse switch on trans or something). Also, if I remember correctly, I think when you turn the lights on, the brake lights turn on too (including the 3rd eye on the cab). I have replaced all the rear bulbs besides the 3rd eye cab light and nothing changed. Also, when I turn the headlights on with the truck off, it does what its supposed to, all the parking/running/corner lights come on, the buzzer goes off (but I cant remember right now if those brakes come on when the lights are on) The brights also dont work, I dont know if its the wiper stick attached to the steering column, but i thought when you pull on the stick towards yourself, its supposed to make a click of some sort that can be felt and then the brights should turn on. To visual inspection the brights bulbs are still good, but my wiper stick doesnt make the click noise when I pull it towards myself. (wiper stick might be called highbeam combo switch, but whatever). Also, when I actually had the cargo light switch plugged in it didnt work. However, when I bought the garbage heap of a truck, it wasnt connected so i figured there was probably a good reason. havent checked the bulbs yet but i thought I should maybe mention it. Any possible shorts that you can think of that are common, please let me know. From what I've been thinking of, it sounds like the brake light signal is tied into the buzzer and running lights/corner lights (and obviously with the brake lights).