Did just put in two new brake pads and turned rotors on the front and two new pads and new rotors on the rear of my 2000 Mercedes S430 how do you reset or clear brake warning light please help?

Try taking the battery cable loose. That works for a lot of cars. I've never had any experience with a mercedes. To reset you brake light or any warning on the S430, just hold down the button (a lil black button on the right side on you instrument cluster) and that will do it. The Brake Sensor warning light will reset itself once the vehicle is restarted. Most common problems are 1. You have a bad sensor or 2. You did not replace the brake the sensors were triggering. There are 3 sensors on the S430 One on each front wheel and 1 on the Right Rear Wheel.