Welcome to AF!
I'm sure you've checked these things, but to make sure I'm listing them. The fuse may be out on the brake lights check STOP fuse. The stop light switch on the brake pedal may be bad, I don't think it can be adjusted. Some have a plunger which can be adjusted and others have a spring loaded switch which can't be adjusted. If everything else checks out, both brake lights may be burned out. I know it's a long shot, but it's happened.
The cruise control won't work until you get the brake lights fixed. It is set up this way so that it will shut off when the brake is actuated. So don't worry about the cruise. It will clear up when you get the other problem solved.