Heating System Hoses are responsible for which function?

• A. Tubes transporting hot coolant to the heater core
• B. Pipes delivering refrigerant to the evaporator
• C. Hoses carrying intake air to throttle body
• D. Lines that vent cabin air to atmosphere

Answer: (A)

Heating system hoses move hot engine coolant to the heater core, which is inside the dashboard. The heater core acts like a small radiator; as hot coolant flows through it, heat is transferred to the air that the blower pushes into the cabin. This is how the car provides warm air inside. The coolant then returns to the engine to be heated again, continuing the cycle.

Other options refer to parts of the air conditioning system (refrigerant to the evaporator), the engine’s intake-air path (air to the throttle body), or venting cabin air to the atmosphere. Those functions are separate from the heater hoses, which specifically carry hot coolant to and from the heater core.