This flashing brake light circuit can be used for motorcycles. When brake-light switch S1 is closed, power is applied to U1 and U2. Two inverters of U2, a 4049 hex inverting buffer, are connected in a ...

They work sometimes with the key off or on but only with the engine not running. Is the brake light circuit still a "simple" circuit (fuse, switch, lights) or does a computer control the lights?