1999 Chevy Monte Carlo Brake problem

When the brakes are applied there is a clicking sound, I figured it was the indicaters for worn pads. So I replaced the front pads and the problem still exists. Also the lights go bright and dim durig braking and the heater motor also runs faster and slower.When setting still pumping the pedal also makes the engine run funny. I used to work on my own cars but its been quite a few years and I am baffled.