A vehicle driven for 15-20 miles and the vehicle's passenger compartment blower motor continues to blow cold air. What is the most likely cause of this condition? A Stuck closed thermostat B Partially restricted heater core C Partially restricted radiator core D Damaged water pump impeller blades

## Step 1<br />The problem presents a situation where a vehicle is driven for 15-20 miles and the vehicle's passenger compartment blower motor continues to blow cold air. The question asks us to identify the most likely cause of this condition.<br /><br />## Step 2<br />The options provided are:<br />A) Stuck closed thermostat<br />B) Partially restricted heater core<br />C) Partially restricted radiator core<br />D) Damaged water pump impeller blades<br /><br />## Step 3<br />The thermostat, radiator core, and water pump impeller blades are all components of the vehicle's cooling system. However, they are not directly related to the temperature of the air blown into the passenger compartment.<br /><br />## Step 4<br />The heater core, on the other hand, is directly responsible for heating the air that is blown into the passenger compartment. If the heater core is partially restricted, it would not be able to heat the air as effectively, resulting in cold air being blown into the passenger compartment.