If the key is on with the engine off, what issue might indicate a bad ignition switch?

A situation where the key turns but there is no power is a strong indicator of a faulty ignition switch. The ignition switch is responsible for powering up various electrical components when the key is turned to the 'on' position. If the key is turned and there is no power to any of the systems—such as dashboard lights, radio, or other accessories—it suggests that the internal contacts within the ignition switch may be worn or malfunctioning, preventing electrical current from flowing.

In this scenario, the absence of power despite the key being turned signifies that the ignition switch is not effectively completing the circuit necessary to send power where it is needed. This is a critical function of the ignition switch, as it not only allows the engine to start but also activates essential vehicle systems when in the 'on' position. A healthy ignition switch should allow for power distribution to various components, signaling its proper function.