The Anatomy of Climate Control in Your Car

The Anatomy of Climate Control in Your Car

As the fall season rolls around, the weather begins to change. The days can still be warm but mornings and evenings can be chilly. In your car, you may turn the heat on in the morning to warm up and clear the windshield but use the AC for the noontime run for lunch. Your car’s climate control system can make the temperature both hot and cold but what does it take to make that happen?

Easy, Breezy

Air movement in your car is provided by the blower motor: An electric motor that sits inside the dashboard. Similar to a household fan, the blower spins and pushes air at different speeds, according to your selection.

Modus Operandi

Once the air passes the blower motor it can travel to a series of vents. The various vent positions are referred to as modes. The usual modes are defrost, face vents, floor vents or some combination. When you choose a mode, an electric motor, called an actuator, turns a series of doors inside the dashboard. The doors direct air from the blower motor to the chosen vents.

‘Core’ Subjects

Once you’ve set the blower speed and selected a mode, how do you get your desired temperature? There are two cores inside the dash, a heater core for heat and the evaporator core for air conditioning.

The Heater Core

The heater core is a small radiator, usually about the size of a hardcover book. Hot coolant flows from the engine, through a hose, into the heater core and leaves through another hose. Air is warmed as it blows across the heater core as it travels to the vents, providing hot air.

The Evaporator Core

The evaporator core lives next to the heater core but carries refrigerant. As refrigerant passes through the evaporator it carries away heat from the inside air, giving you that ice cold AC.

Mixing It Up

There are days when you need the heat on full blast and there are times when you want to feel like an ice cube. But what if you want to set the temperature somewhere in the middle? A blend door is the answer.

As with the mode doors, an actuator is used to control the blend door. Air is directed over the heater and evaporator cores, blending hot and cold to create the temperature you chose.

You Make the Call

Many cars offer automatic climate control. Using a variety of sensors measuring in-car temperature, outside temperature, level of sunlight and other information, the vehicle will decide the proper blower speed, mode and blend door position. You can also take control and chose the mode, speed and temperature yourself.

Inside/Outside

All vehicles have a choice to draw in fresh air or recirculate the inside air. The recirculate button often has an outline of a car with a U-shaped arrow inside it. Recirculating the inside air helps achieve the desired temperature quicker versus allowing outside, unconditioned air into the vehicle.

Most vehicles will automatically turn off recirculation when the defroster is on. You may have experienced foggy windows, especially on a damp or rainy day. Opening the windows will help to clear them quickly. In the same way, the defroster works best with fresh outside air to keep the windshield clear.

The Way, Way Back

Where it was once only found in vans and large SUVs, it has become increasingly common to have rear heat and air conditioning in sedans and other small vehicles. These vehicles will have a second set of actuators, heater and evaporator cores and temperature controls for the folks in the back to control their settings.

We Can Help

If you find yourself without air conditioning on a hot afternoon, don’t sweat it! If you can’t get your heat up to temperature, don’t lose your cool! BBack Car Care can service and repair your vehicle’s climate control system. Request an appointment online or call to schedule an appointment.