Brake light on and off depending on break pedal pressure on startup
 

2014 A8L 3.0L Before starting the car if I pump up the break pedal hard and the Parking Brake is on or off the red brake light will not come on as long as I keep pressure on the brake pedal. I can cycle the EPB and light goes on and off correctly still not red brake light on dash as long as I keep steady pressure on brake peddle. The second I let off the pedal the red brake light comes on and will not reset unless I restart the engine pumping the brake peddle and then keep a firm foot on the peddle. Otherwise the red light comes on. The error message Break Pad! comes up for a few seconds. It was doing this before yesterday when I did replace the rear pads and wear sensor wires. The correct procedure of releasing the EPB was used in the installation. The mechanic is an Audi mechanic but not done at Audi dealership. If it was the sensors would the develish red light go off as I increased breaking pressure with the foot brake? Of course this was done without moving. Scanned car and zero codes are triggered. The mechanic is puzzled and could use some help from you that are more experienced with the brake light. How could the brake pads put enough pressure on the pads to disable the pad sensor error? Thanks