On my car at least, the seat belt buzzer gets its power from the kickdown switch plug....my seat belt warning system didn't work....I was testing the voltage from the kickdown switch plug and it started working again....there was some corrosion built up inside the plug....once cleaned its been working perfect....

The only thing that is controlled by the brake peddle is the break lights and cruise control amp....when the peddle is pressed....it sends 12v's to the lamps and breaks the ground to the cruise control amp...telling it to shut off......the ground for the brake lamps is in the trunk....

I would go around and clean all the ground points....

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