Diodes may be found on all of the following components except which?

• A. Alternator regulator
• B. Headlights
• C. Power window switches
• D. Starter solenoids

Answer: (C)

Diodes are used to direct current flow and protect circuits in automotive electrical systems. In an alternator, the rectifier diode bridge converts the AC generated by the alternator into DC to charge the battery, so diodes are a fundamental part of that component. In headlights, especially modern LED units or their driver circuitry, diodes show up as part of the power regulation and protection network. Starter solenoids often involve diodes in their control paths or suppression circuits to handle back-EMF and protect the rest of the wiring and switchgear.

A power window switch, however, is simply a control that routes battery power to the window motor to move the glass up or down. It doesn’t require diodes for its operation, so diodes are not typically found inside the switch module. The motor itself or its driver circuitry may include suppression components elsewhere, but the switch unit itself doesn’t rely on diodes.