How do you turn the window heat on without the engines running?

To activate the window heat without the engines running, placing the PROBE/WINDOW HEAT switch to the ON position is the correct method. This switch allows for the manual activation of the window heating system, which is crucial to prevent ice accumulation on the cockpit windows during flight or while on the ground.

In contrast, setting the switch to AUTO would not activate the system effectively without the engines or the Auxiliary Power Unit (APU) providing necessary electrical power. Starting the APU would be a valid approach to power many systems, but it is not directly related to the immediate action of turning on the window heat. Pulling the AUTO mode circuit breaker is not relevant in this context as it disables the automatic function rather than activating the window heat. Thus, directly switching to ON provides the quickest means to ensure that the window heating is operational without reliance on engine power.