The car's outside temperature sensor, often called the ambient air temperature sensor, is typically located in the front of the vehicle. You'll most often find it behind the front grille, near the bumper, or integrated into the side mirror housing. This placement allows it to read the air temperature outside the car accurately, away from engine heat. The reading is then displayed on your dashboard or climate control screen.
Its location is strategic but has a downside. When you're stopped in traffic or moving slowly, the sensor can pick up radiant heat from the engine and road surface, showing a temporarily higher temperature than the actual outside air. This is why the reading is most accurate after you've been driving at a consistent speed for several minutes.
If your temperature display is incorrect or shows dashes (--), the sensor itself might be damaged, its wiring could be corroded, or the connector is loose. Common issues include impact damage from road debris or washing the engine bay. Diagnosing this usually requires a basic multimeter to check the sensor's electrical resistance, which changes with temperature.
| Common Sensor Locations | Potential Issues if Malfunctioning | Approximate Replacement Cost (Parts & Labor) |
|---|
| Behind the front grille | Inaccurate reading on dashboard | $75 - $150 |
| Integrated into side mirror | Incorrect automatic climate control | $100 - $200 (more for mirror assembly) |
| Near the front bumper | Display showing "---" or "ERR" | $80 - $175 |
| Under the front fender liner | A/C not cooling efficiently | $70 - $160 |
To get the best reading, pay attention to the temperature after you've been on the highway for a few miles. If you suspect it's wrong, a simple check is to compare it with a known-accurate source, like a weather app on your phone, once you are moving. Replacing the sensor is generally a straightforward job, but the cost can vary significantly depending on its location, especially if it's part of an expensive side mirror assembly.
