1995 Chevy Tahoe brake lights

Electrical problem
1995 Chevy Tahoe 6 cyl Four Wheel Drive Automatic

our brake lights went out and we checked the fuses and the bulbs and nothing was wrong. So we had the brakelight switch changed and we had an issue with not being able to shift out of park. It has been adusted and the lights worked everything was fine until this morning and the same thing happened. No lights and not being able to shift. I am ata loss in what the problem could be.