Weird circle on your car dashboard actually has a purpose

Nowadays, even the average car is littered with some great features, when just a few years ago only the top-end vehicles would be blessed with things like a Sat Nav or a touchscreen control centre.

We really are spoilt with how much cars come with these days, as the latest technology makes its way into the interior and often the exterior of models around the world.

One example of outstanding modern day engineering are the frits on your windscreen - almost every car has them, but without explicitly looking for them, you wouldn't notice.

But by preventing the Sun from damaging the adhesive that connects your window and windshield, they provide structure and safety to your vehicle.

But there's a feature on some older cars that you probably won't know much about, despite definitely seeing it before.

It's that weird circular panel on the dashboard.

Have you noticed the little circle before? (YouTube/BT Build Things)

Well, it's called a solar or sunload sensor.

It looks like a round knob at the back of your dashboard, and though most are circular, some can stick up, and others blend in with the surface - the point is, it's there.

It turns out that its role in your car is quite important, even though someone has probably never explained it to you before.

Auto Service World, a Canadian automotive aftermarket industry magazine, revealed exactly what it is, and how it help us in our cars.

The site explains: “Sunload sensors are usually located at the top of the dash and are often mounted on a removable plate, speaker grill, or defroster vent,

“There is often one on either side of the dash to accommodate differences in sunlight exposure.”

As its name entails, it is responsible for monitoring how much sunlight reaches the inside of your vehicle, and it's a crucial part of the climate control system.

“Sunload sensors monitor the intensity of sunlight and adjust the HVAC [heating, ventilation, and air conditioning] control to improve the comfort level of the driver and passengers on sunny days,” Auto Service World adds.

You can thank that tiny circle on your dashboard for the cool air-conditioning in the summer. (Getty Stock Image)

“Bright sunlight conditions can result in the fan speed increasing, and blend doors opening to improve cooling,” the site continues.

Essentially, it works with something called a photodiode, a semiconducting diode which converts photon radiation, into electrical current - and in this situation, the photon radiation is visible light.

So as the light intensity increases, the resistance of the diode does as well, which unfortunately means that fewer volts make it to the car's smart internal monitoring systems.

The control module then takes this sign as a signal to boost the air-conditioning preventing you from getting cooked in a metal box.

But your car may have a faulty HVAC system, which puts you at risk of overheating in your vehicle due to the system being unable to sense the heat.

“Sunlight entering a vehicle can account for up to 60 percent of the interior heat load that the system must overcome,” Auto Service World states.

Basically, that little thing on your dashboard is one of the most important features in your car, as it keeps the environment at a comfortable temperature and away from overheating.

Thanks, sensor.