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How to Change Ambient Air Temperature Sensor

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What is Ambient Air Temperature Sensor

The ambient (ATC) or external air temperature sensor is a negative temperature coefficient (NTC) sensor, which notifies the external air temperature to the semi-automatic/automatic temperature control system. With the increase of external air temperature, the resistance of NTC sensor will decrease. The computer uses this input and other in-car temperature sensors to control temperature and blower speed. When the sensor has problems, the performance will be affected, and the compressor clutch may not mesh.

Symptoms of ambient air temperature sensors, such as clutches that do not work or input problems, are diagnosed with scanning tools and multimeters. Factories and many general scanning tools can activate certain components; compressor clutch is one of them. If the clutch engages with the scanning tool, one of the inputs may be problematic. Verify any doubt by visual inspection of the sensor and its connectors. Use the multimeter and verify the manufacturer’s specifications (range from 220 to 240 ohms at 70 to 80 degrees F) to test whether the sensor has an appropriate resistance.

For an example, the automobile air conditioning system uses NTC sensors to monitor air temperature. The in-car temperature sensor (ICTS) is an NTC used to monitor the air temperature in the passenger compartment. The environmental temperature sensor (ATS) monitors the air temperature outside the vehicle. EATC compares these values and makes output decisions based on the differences in these temperatures.

Remove Old Environmental Temperature Sensor

Step 1: Disconnect the battery. Disconnect the grounding connection with the battery. Cutting off battery power is critical to safety when using any type of electrical system on a vehicle.

Step 2: Find the sensor. You can find the ambient air temperature sensor in the front of the engine compartment.

Usually, the sensor is located behind the grille, but in front of the radiator and radiator bracket. This is the best position for the sensor because it is far from the heat of the engine and can accurately read the ambient temperature of the surrounding air; that is, the air temperature entering the front intake manifold of the engine. Usually, automobile manufacturers try to make these sensors accessible but protected. You may have to remove part or all of the front grille to use the sensor.

How to Change Ambient Air Temperature Sensor
How to Change Ambient Air Temperature Sensor

Step 3: Disconnect the sensor. Usually, you can disconnect these temperature sensors from their wiring and then screw them out or release them. Connections are fed into “terminals” or plastic clips so that you can easily disconnect the wires without having to do a lot of electrical work. Loosen the wires and put them aside. Some are fitted with additional bolts because the sensor itself is not connected to any part of the vehicle. It may also be necessary to install a bracket to keep the sensor in place.

Step 4: Remove the sensor. Then, you should be able to pull out, twist out or loosen the sensor or pull it off the bracket. After removal, check the sensor for any significant damage.

The ambient air temperature sensor is located in the relatively sensitive position in the front of the vehicle. Any damage to the front bumper or grille may cause problems with the sensor. If not properly protected, everything that hits the grille while you are driving may hit the sensor. If the ambient temperature sensor fails due to problems with the surrounding components, these problems need to be addressed before you waste money and time replacing new equipment. If not addressed, these problems may lead to the failure of your new sensor.

Install a New Sensors

Step 1: Insert a new sensor. Insert the new sensor in the same way as removing the last sensor. On the new sensor pop-up, tighten, clamp or tighten, it should match the other completely.

Keep in mind that some of the newer replacement parts are designed slightly differently and may not look exactly the same. However, they should fit in and insert exactly the same position as the old sensor.

Step 2: Reconnect the terminal. Insert the existing terminal into the new sensor. New sensors should accept existing wires like old components.

Note: Do not force the terminal into its corresponding terminal. They may be stubborn, but breaking them and having to reconnect new terminals can be time-consuming and costly. They should click and stay in place. When using, please check terminals to ensure that they are in good condition.

Step 3: Reinstall all deleted components for access. After inserting the sensor, you can reconnect any part of the grille or radiator cover you unload to contact the sensor.

Step 4: Reconnect the negative battery terminals. Reconnect the negative battery terminals. At this point, you are ready to adapt the vehicle’s computer to the new sensors.

Step 5: Test drive your car. Sensors and computers need a little time to communicate. Once they are connected to each other, your vehicle monitor should read correctly.

Preheat the vehicle and set it to a temperature below or above the outdoor ambient temperature. If necessary, drive the vehicle while testing the automatic temperature controller. You can also do this test in parking mode. Vehicle manufacturers try to use the same sensors to perform different functions. Ambient air temperature sensors can have different effects on the performance of automatic air conditioning and heating systems. It also affects the readings on the external temperature driver display.

You can easily and economically replace the environmental temperature sensor yourself. If you are not familiar with the process, please get certified technicians from YourMechanic to replace the environmental temperature sensor in the most suitable location for your needs.


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