Where Is The Outside Temperature Sensor On A Car?

Automobiles are manufactured with several components working in synergy to deliver a satisfactory driving experience. The outside temperature sensor is a vital component that determines how a car responds to changes in temperature.

Replacing the temperature sensor is impossible if you can’t identify the component’s location. Meanwhile, a bad outside temperature sensor will result in a couple of malfunctions in a car.

Therefore, if you’re wondering, “Where is the outside temperature sensor on a car?” Make sure you study this article till the end to find out the component’s location and how it works.

how to reset outside temperature gauge in car

How Do Cars Measure Outside Temperature? 

If you’re contemplating, “How do cars measure outside temperature?” Cars are fitted with a device known as a thermistor, which helps to determine temperature levels, by measuring the variations in electrical current whenever the sensor perceives increased or reduced heat.

The thermistor is always active, sending signals to the computer system in a vehicle. However, the signals may not always be accurate due to the position of the outside temperature sensor in the car.

The sensor is usually located in a place exposed to the road surface. This has a great impact on how well the sensor picks temperature signals. In most cases, it will not be able to send the correct signals to the computer system.

So, if you were wondering, “What is the outside temperature sensor, and where is it located in a Toyota?” Kindly check out this video for a visual explanation of the component’s location in your Toyota car.

Where Is The Outside Temperature Sensor On A Car?

The outside temperature sensor (thermistor) is located in front of a vehicle beneath the hood behind the grill area. The position of the sensor is a critical factor that interferes with the accuracy of the temperature signals it sends to a car’s ECU.

Since the sensor is located in front of the car near the road surface, it usually picks the temperature from the heat on the road even when the atmospheric temperature is relatively lower.

In other words, the outside temperature sensor does not usually send accurate information. There is a high tendency for the sensor to communicate a temperature level higher than the ideal.

Therefore, if your car’s outside temperature gauge is reading high on your car’s dashboard and the atmospheric temperature is relatively low, don’t panic. It is not necessarily a fault to worry about. The position of the outside temperature sensor is the reason for the occurrence.

Where Is The Outside Temperature Gauge On A Car?

A car’s outside temperature gauge is located in front of the car, behind the grill under the hood. The device sits near the engine compartment and the hot asphalt pavement.

The factors surrounding the temperature gauge are a major reason you shouldn’t always trust the temperature readings on the dashboard screen. The road surface is usually hot, thereby influencing the message from the sensor.

Sunny days usually come with the worst experience. This is because the sun hits hard on the asphalt, causing the heat to radiate from the road’s surface. When the temperature gauge picks up the heat from the road, it sends the signal directly to the engine control unit (ECU).

Meanwhile, all vehicles have been designed to work efficiently with a recommended ambient temperature of Fahrenheit. Otherwise, the engine may be exposed to overheating due to extremely high temperatures.

Why Is My Car Reading The Wrong Temperature Outside?

Your car is reading the wrong temperature outside because the thermistor is picking the heat radiation from the hot road surface instead of the atmospheric temperature. The position of the sensor is the reason for the inconsistency.

While you expect to receive the signal of the outside air temperature, the sensor concentrates more on the temperature from the road because it is mounted close to the asphalt on the road. As a matter of fact, the readings are usually higher on a hot summer day.

Typically, you should expect to see temperature readings around 10 – 20 degrees more than the normal atmospheric temperatures on sunny days. This occurrence doesn’t mean that something is wrong with your car; the sensor is simply responding to the heat from the road surface.

What Is The Perfect Temperature Outside For Humans?

The ideal outside temperature for humans is around 70 degrees Fahrenheit. The temperature at this level helps the body to function optimally. Generally, humans prefer warm temperatures to cold temperatures.

In fact, vehicles are expected to operate between 195 – 220 degrees Fahrenheit. Anything above the ideal temperature will put more strain on the air conditioning system, negatively impacting the engine.

Typically, overheating is a major cause of engine damage. Therefore, keeping the engine within the recommended temperature level should be a maintenance priority. However, in any case, you may not be able to rely on the signals from your temperature sensor due to inconsistency.

How Do I Know If My Ambient Temperature Sensor Is Bad?

Some of the symptoms that reveal a bad temperature sensor include inconsistent AC cooling, inaccurate outside temperature readings, and a defective AC auto mode. Since the sensor relates to other components in a vehicle, a slight malfunction will affect the other parts.

Usually, the higher the atmospheric temperature, the more your car’s air conditioning system works. So, if the component becomes faulty, it will most likely fail to send accurate signals to enable the air conditioner to function properly.

Moreover, a malfunction in the HVAC system will eventually interfere with the engine’s proper functioning, resulting in more stress on the car. Therefore, if you discover a faulty outside temperature sensor (thermistor) in your car, ensure to replace the component immediately.

Even though the bad sensor may not hinder your car from moving, it will alter the proper functioning of related components. This may gradually result in further damage. Ensure to avoid unnecessary complications that you can easily avert initially.

How Do You Test An Outdoor Temperature Sensor?

You can use a digital multimeter to test whether your car’s ambient temperature sensor is working or not. The process is pretty straightforward. Simply get a working multimeter, a small bowl, and some water. Then, follow the step-by-step guide below.

Locate the thermistor sensor

Firstly, ensure that your car’s engine is off and cool while you open the hood to access the sensor. The sensor is located near the thermostat. It is a little black device plugged into a specific wire harness.

However, the location may differ in some cases, depending on your vehicle’s make and model. Therefore, you may want to check out the exact location from your owner’s manual.

Unplug the sensor

Once you identify the outside temperature sensor, gently unplug it. Carefully hold the wiring harness with one hand and pull the sensor from the body with the other hand. Then, keep the sensor on a desk or table and push the wiring harness back in place.

Fill the bowl with water and ice.

Now, put some water of around 6 ounces (180 mL) inside the bowl and add some ice cubes to reduce the temperature. Allow the temperature of the water to reduce to around 33 degrees Fahrenheit. You can verify this with a thermometer.

Connect the multimeter to the sensor

Get the multimeter leads and connect them to the outside temperature sensor. First, connect the red lead to one of the multimeter’s connectors either at the left or right extreme. Then, connect your black lead to the connector on the far side of the red to prevent them from touching each other.

Turn on your multimeter and set it to DC.

Once you finish connecting the leads from the multimeter to the sensor, turn on the multimeter and switch it to DC. This will give a voltage reading you can use to test the sensor properly.

Dip the sensor into the water and check the reading

Now, dip the outside temperature sensors into the bowl of water and observe the reading. Carefully dip the device from the tip until it is covered in water.

Then, check the reading. Ideally, you should get around 5 volts. Once you get the reading, kindly write it somewhere. If you don’t get any reading, you may have to reconnect the leads properly and test the sensor again.

Test the sensor in hot water

This time around, get the same quantity of water, around 6 ounces (180 mL), and heat the water in a pot using a stove or cooking gas. After boiling the water, pour it into a container or mug that can hold the content and dip the sensor carefully into the water.

Then, check the reading after a few seconds. You should get a reading of around .25 volts. Once you see the result, note it down also.

Compare the results with your car’s ideal temperature readings

Now, check for your car’s ideal outside temperature sensor readings online. You will find the readings for both hot and cold temperatures. If the results tally with what you have, it means the sensor is okay. If it varies widely, you may have to replace the component.

How Do I Replace My Ambient Air Temperature Sensor?

Replacing a faulty outside temperature sensor is quite easy. It also involves the step-by-step procedure that enables you to test the component with a multimeter. However, the following steps below will help you replace your car’s faulty thermistor.

Step 1: Disconnect the battery’s negative terminal

First and foremost, kindly remove the cable on the battery’s negative terminal. This will help you avoid electrocution while you work on the components. In fact, always disconnect your battery’s negative terminal when working on electrical components in your car for safety.

Meanwhile, ensure that the car is off and the engine is cool before you start performing any operation within the engine bay.

Step 2: Locate the outside temperature sensor

Now, pop the hood open and trace the outside temperature sensor. The component is usually located close to the thermostat or the radiator behind the grill.

However, the exact position may vary depending on your car’s make and model. So, kindly verify from your car manufacturer’s manual.

Step 3: Unplug the current sensor

Once you identify the sensor, now is the time to unplug it from the wiring harness where it is connected. So, carefully hold the sensor with one hand, hold the wiring harness with the other hand, and detach the two carefully.

Step 3: Install the new sensor

Get the new outside temperature sensor and fix it in the reverse order in which you unplugged the old one. Then put the wiring harness in place properly.

Step 4: Reconnect the battery’s negative terminal.

Lastly, reconnect the cable on the negative terminal of the car’s battery. After that, start the car and go for a test drive to verify whether the job was properly done.

Does Outside Temperature Affect Car Air Conditioner?

Yes, the outside temperature sensor may affect the air conditioning system once it becomes defective, resulting in inconsistent readings. Generally, the hotter the temperature outside, the more the air conditioner has to work.

In other words, a faulty outside temp sensor will send false signals to the car’s engine control unit (ECU), which further impacts how other components respond, including the air conditioning system.

Therefore, if you constantly receive false signals from your car’s outside temp sensor, kindly test the component with a multimeter. If you discover that the sensor is bad, ensure to replace it immediately.

How Much Does It Cost For an Outside Temperature Sensor?

The estimated cost of replacing a defective outside temperature sensor varies from $40 to $250, depending on the vehicle’s make and model. The location of the auto technician fixing the component can also impact the overall cost.

In any case, fixing the component is worth it. However, if your car’s outside temperature sensor is not working and probably needs a replacement, you may want to check out the auto parts shop near you across the street.

Final Words

Although inaccurate readings are common with a vehicle’s an outside temperature sensor, it is also important to ensure that the inconsistency is not due to a bad sensor. If you have a faulty sensor that needs replacement, kindly get one ASAP.

If you’re a DIYer and you’re asking, “Where is the outside temperature sensor on a car?” The component is fitted somewhere in front of your car under the hood behind the grill. Once you identify the component, carefully follow the procedure above to replace it.

However, if you’re not sure of doing the job perfectly, ensure to contact an expert auto technician to replace the component for a few bucks.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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