Use brake-lamp behavior, cruise-cancel symptoms, and scan-data logic to separate a bad brake-pedal switch from wiring, fuse, or adjustment problems.
The brake-light switch often feeds more than one circuit or more than one module. That means the lamps can appear mostly normal while the PCM still sees an implausible brake-applied signal and stores P0504 or P0571. If the brake lights, cruise cancel behavior, and scan-tool brake-switch PID do not all tell the same story, do not assume the bulbs proved the switch is good.
A misadjusted or loosely mounted switch often creates an intermittent story. Cruise may refuse to set, the brake lights may come on too early or too late, and the signal can change when the pedal is barely touched. That pattern is different from a blown fuse or dead lamp circuit, which tends to fail more cleanly.
P0572 points toward a low-biased brake-switch signal, while P0573 points toward a high-biased or always-applied story. Those codes help you think in circuit logic: short to ground, short to power, missing feed, poor connector fit, or the wrong switch installation can all make the module believe the brake pedal lives in the wrong state.
If cruise control quit at the same time the code appeared, or if shift interlock behavior feels odd, the switch path deserves top billing. Those extra symptoms matter because they prove the brake-applied signal is being used beyond lamp illumination alone.
First verify lamp operation and check for lamps stuck on or delayed. Second compare scan-data brake-switch status with actual pedal movement. Third inspect switch mounting, connector fit, and the pedal contact point. Fourth widen the diagnosis to fuse, wiring, or shared voltage problems only after the switch story stops making sense.