The main switch on the steering wheel seems to stay latched and the CRUISE light on the instrument cluster is on. The brake lights seem to be off when the brake is released on on when it is pressed. Still, the cruise will not engage or set when I press the set button.

 

You could try (temporarily!) bypassing the brake pedal switch, to make sure.

But it could have lost a speed signal input, or even the set/resume button.

Quickest way might be to run a diagnostic.