Ever wondered why your truck’s temperature reading is way off? Your Ram’s ambient temperature sensor might be the culprit. This small but crucial component helps your vehicle display the outside temperature and affects your climate control system’s efficiency. Let’s explore where this sensor hides in different Dodge Ram models and how to fix common issues.
Where Is the Ambient Temperature Sensor on Newer Ram Trucks (2019-Present)?
In the latest generation Ram trucks (2019 and newer), Dodge placed the ambient temperature sensor in the driver’s side exterior mirror. This location helps the sensor get an accurate reading of the outside air temperature while protecting it from engine heat.
The sensor is specifically located:
- At the bottom of the driver’s side mirror stalk
- Visible through a small hole in the mirror housing
- Accessible via a removable panel or clip on the mirror
You don’t need to remove the entire mirror to access it. The sensor can be easily removed by pressing a pinch clip and pulling it out, making replacement a simple DIY job.
Ambient Temperature Sensor Location in 2010-2018 Ram Models
For Ram trucks manufactured between 2010-2018, the sensor location varies slightly. Most models from this generation also have the ambient air temperature sensor in the driver’s side mirror housing, similar to newer models.
However, some early models in this generation might have a different placement. If you can’t find it in the mirror:
- Check behind the front grille
- Look near the radiator support on the driver’s side
- Examine the area behind the front bumper cover
Third Generation Ram Trucks (2002-2009) Sensor Location
If you own an older Ram from the third generation (2002-2009), you’ll find the ambient temperature sensor in a completely different spot. For these models, Dodge placed the sensor:
- Behind the front grille on the radiator support
- Typically on the driver’s side of the radiator support area
- Connected with a simple two-wire electrical connector
This location was chosen to shield the sensor from direct engine heat while still allowing it to measure outside air temperature.
How to Identify a Failing Ambient Temperature Sensor
Your Ram’s ambient temperature sensor might be failing if you notice these symptoms:
- Temperature reading shows an extreme value like -40°F or over 126°F
- Display shows two dashes instead of a temperature reading
- Check engine light comes on with code P0073 (ambient temperature sensor circuit high input)
- Temperature readings that don’t change despite obvious weather changes
Why Your Ram’s Temperature Reading Might Be Inaccurate
Even when working correctly, your temperature sensor might show inaccurate readings in certain conditions:
Heat Soak Effect
Mirror-mounted sensors can display artificially high temperatures when parked in direct sunlight. The mirror housing absorbs heat and can cause readings of 120°F+ even when the actual temperature is around 100°F.
This is known as “heat soak” and is common in Ram trucks with mirror-mounted sensors. The good news? This typically normalizes after driving for 3-4 miles when airflow cools the mirror housing.
Other Factors Affecting Accuracy
- Traffic congestion: Sitting in heavy traffic can cause elevated readings due to heat from surrounding vehicles
- Driving at very low speeds: Insufficient airflow might prevent the sensor from cooling properly
- Recent rain or snow: Can temporarily lower temperature readings
Replacing Your Ram’s Ambient Temperature Sensor: Step-by-Step Guide
For Mirror-Mounted Sensors (Newer Models)
Tools needed:
- Small flathead screwdriver or trim tool
- Replacement sensor (Mopar part)
Steps:
- Locate the sensor at the bottom of the driver’s side mirror
- Identify the small access panel or clip covering the sensor
- Gently remove the access panel using a trim tool
- Press the pinch clip to release the old sensor
- Unplug the electrical connector
- Connect the new sensor and insert it until you hear a click
- Replace the access panel
Cost: A genuine OEM Mopar sensor costs approximately $14-15, making this an affordable DIY repair.
For Grille-Mounted Sensors (Older Models)
Tools needed:
- Basic hand tools for grille removal (typically screwdrivers)
- Replacement sensor
Steps:
- Locate the sensor behind the grille on the radiator support (driver’s side)
- You may need to remove or partially loosen the front grille for access
- Unplug the two-wire electrical connector
- Remove the old sensor (usually twist or clip mounting)
- Install the new sensor and reconnect the wiring
- Reinstall the grille if removed
Common Replacement Parts and Where to Find Them
When replacing your Ram’s ambient temperature sensor, you have several options:
| Part Type | Typical Cost | Where to Purchase | Part Numbers |
|---|---|---|---|
| OEM Mopar | $14-20 | Dealership, Online Mopar parts retailers | 56042395, 5149265AB |
| Aftermarket | $10-15 | AutoZone, O’Reilly, online retailers | Varies by manufacturer |
| Used/Salvage | $5-10 | Salvage yards, eBay | OEM numbers |
For most owners, an OEM Mopar sensor provides the best reliability, but quality aftermarket options work well too. Just make sure to get the correct part for your specific truck year and model.
Avoiding Damage to Your New Ambient Temperature Sensor
After installing a new sensor, keep these tips in mind:
- Avoid pressure washing directly at the mirror housing (for mirror-mounted sensors)
- Be careful when using automatic car washes with aggressive brushes
- Don’t use harsh chemicals near the sensor when cleaning your truck
- If removing the mirror for any reason, be careful not to damage the sensor wiring
The Importance of an Accurate Ambient Temperature Sensor
Your Ram’s ambient temperature sensor does more than just display the outside temperature on your dashboard. It also:
- Helps the climate control system operate efficiently
- Provides data for the engine management system
- Assists with defrost functions in cold weather
- May trigger cold weather alerts when temperatures approach freezing
An accurate reading ensures all these systems work properly, potentially saving fuel and preventing unnecessary wear on your truck’s components.
Temperature Sensor vs. Other Sensors: Don’t Get Confused
Don’t confuse the ambient temperature sensor with other sensors in your Ram:
- Intake Air Temperature (IAT) Sensor: Located near the engine air intake
- Engine Coolant Temperature Sensor: Found on the engine block or cylinder head
- A/C Refrigerant Temperature Sensor: Part of the air conditioning system
The ambient temperature sensor specifically measures outside air temperature and is not directly involved in engine management.
Diagnosing Sensor Issues Without Special Tools
If you suspect your ambient temperature sensor is faulty but don’t have diagnostic tools, try these simple tests:
- Compare readings: Check the displayed temperature against a reliable thermometer
- Monitor for changes: The reading should change gradually as you drive from hot to cold areas
- Watch for extremes: Readings of -40°F or 126°F+ typically indicate sensor failure
- Inspect for damage: Look for physical damage to the sensor or wiring
A failing sensor will typically show consistent problems regardless of driving conditions or time of day.
By understanding where your Ram’s ambient temperature sensor is located and how to diagnose common issues, you can keep your truck’s climate control system working properly and avoid unnecessary diagnostic fees. Whether you have a brand new Ram or an older model, this small component plays a bigger role than you might think in your everyday driving comfort.
