There is a small plastic button pressed into the brake pedal housing that pushes against the brake switch mechanism up the neck of the brake pedal. It has disintegrated. This is a dealer only item and the parts department is very well knowledgeable regarding the problem. The button is way over priced. Get 2 while you're there because the plastic button located next to the brake button will disintegrate as well, very soon. Both of mine(they are identicle) fell apart as I was examining the problem. The other one is used for the cruise control turn off switch. If it becomes dysfunctional your cruise control will always think you are stepping on the brake, thus, it will not turn on.Plan on readjusting them both if you DIY. The size of the dealer's replacement part is off by about a millimeter in thickness and will probably not work correctly if you don't readjust the switches after you install the button. Good luck.
there is a switch and a rubber bushing on the brake peddle the bushing probly fell out of the brake when you release the brake the switch is probly just going in the hole where the rubber bushing is suppose to be replace the bushing inspect brake peddle and if it missing go to parts place and get one and install
The button on the brake pedal has disintegrated, and the normally open brake switch plunger is never depressed while the pedal is up. I recommend that you remove the pin connecting the master cylinder and brake pedal together. First remove the retaining clip, then pinch the end of the flared nylon together, and pull out the pin. Take some slender needle nosed pliers and while pushing the pedal forward, insert the part with the smaller (ball) portion towards the motor compartment into the hole on the tabbed portion of the pedal. Pull the pedal back towards the driver's seat, and it should snap in. One may lubricate it if desired. The Nissan part number is 46584-5P010 and cost me $9.98 plus sales tax.