To read a heater core diagram, you need to understand the concept of exploded view drawings. Most heater core diagrams are created in this way in order for you to be able to see all of the components. The largest components in any heater core diagram are typically the individual sections of the heater box, which may split into two or three parts with lines drawn to show how they fit together. Other components to look for are the heater core itself, any control valves, air doors, and vents. Each component is drawn to look just like the actual item, so you can use these diagrams to see exactly how everything fits together.
Exploded view diagrams are designed to show every component of an object in relation to each other part. Lines will typically be drawn between different parts of the object to show how they fit together, which can be useful in both disassembly and reassembly. Since the components are all drawn realistically, these diagrams can also be useful to identify individual components for replacement. Some of these diagrams also include part numbers next to each component to further assist in repair work.
When viewing a heater core diagram, the largest components are typically pieces of the heater box. You can look at these components and how they fit together to get an idea of what the heater box is shaped like and how it fits into the vehicle. In many cases, you can even see how many bolts or studs the heater case is fastened with and where they are located, which is information you may use to extract it more quickly. A heater box sometimes needs to be taken out in pieces, so a heater core diagram can also show you how to do that.
It is typically also possible for you to locate other components using a heater core diagram. The heater core itself will usually be represented fairly accurately, so you can easily determine how it fits into the heater box and where it is located. Some vehicles allow you to remove only one part of the heater box and then slide out the core, which you will usually be able to determine from the diagram. This can save you a lot of time compared to how long it would take to remove the entire box.
The orientation of any vents or air doors can also be determined from the diagram, which can be useful when reassembling the heater box for reinstallation. Other components are typically visible in these diagrams as well, such as the blower motor, vacuum switches and motors, and ballast resistors. You can use this information for diagnostic or repair purposes, and it will save you the time of searching around for where the components are located.