Engage the High Idle Switch on emergency scene or whenever idling for prolonged periods.

Engage the High Idle Switch on emergency scene or whenever idling for prolonged periods.

• A. Low Idle Switch
• B. Cruise Control
• C. Parking Brake
• D. High Idle Switch

Answer: (D)

Engage the High Idle Switch when you need more engine RPM while idling to keep essential systems powered and ready. Raising the engine speed above normal idle increases the alternator output so lights, radios, fans, and other equipment can run reliably, and it helps prevent stalling during prolonged idle or at an emergency scene. Low Idle Switch does the opposite, reducing RPM to save fuel and noise, which isn’t helpful when you need more electrical and pump capability. Cruise control keeps a set speed and isn’t used to boost idle readiness. Parking brake is for securing the vehicle and has no impact on idle speed or system readiness.

Engage the High Idle Switch when you need more engine RPM while idling to keep essential systems powered and ready. Raising the engine speed above normal idle increases the alternator output so lights, radios, fans, and other equipment can run reliably, and it helps prevent stalling during prolonged idle or at an emergency scene.

Low Idle Switch does the opposite, reducing RPM to save fuel and noise, which isn’t helpful when you need more electrical and pump capability. Cruise control keeps a set speed and isn’t used to boost idle readiness. Parking brake is for securing the vehicle and has no impact on idle speed or system readiness.