In a power window system, which component handles switching current to the motor?

• A. Relay
• B. Fuse
• C. Switch
• D. Sensor

Answer: (A)

The ability to turn the motor on and off in a power window system is provided by a device that can handle high current: a relay. The window switch you press sends a low-current signal to energize the relay coil. When the coil is energized, the relay’s contacts close and complete the high-current path from the battery to the motor, letting current flow and the window move. This separation protects the switch from carrying heavy current and ensures the motor can draw the current it needs, including the startup surge.

A fuse is for protection, not for switching operation; it will interrupt current if there’s a fault but doesn’t actively control the motor. The switch itself provides the control signal but typically does not carry the motor’s high current directly. A sensor is used for monitoring or safety functions, not for switching the motor.