Ram 3500 Engine Coolant Temperature Sensor Guide (2016-2024)
Keep your Ram's engine running right by understanding, diagnosing, and replacing a faulty coolant temperature sensor.
- A bad ECT sensor can cause a check engine light, poor fuel economy, and incorrect temperature gauge readings.
- Replacement on the 6.7L Cummins is very easy and located near the thermostat housing.
- Do not confuse the temperature sensor with the coolant LEVEL sensor, which is in the reservoir tank.
- For this part, spending a few extra dollars on an OEM or top-tier aftermarket brand like Delphi or Standard is a smart investment to ensure reliability.
Is Your Ram 3500's Engine Acting Up? It Could Be The Coolant Temp Sensor
A failing Engine Coolant Temperature (ECT) sensor can cause a surprising number of problems in your 2016-2024 Ram 3500. Because the truck's computer relies on this sensor for so much information, a bad signal can lead to poor performance, a check engine light, and other confusing symptoms. Understanding these signs is the first step to getting your heavy-duty truck back in top shape.
Symptoms of a Bad ECT Sensor
Watch for these common signs of a failing coolant 🎬 Watch: A quick visual guide to bad coolant sensor symptoms. temperature sensor:
- Check Engine Light: This is often the first warning. You may see codes like P0117, P0118, or P0116.
- Inaccurate Temperature Gauge: The gauge on your dashboard might stay on cold, even when the engine is fully warmed up, or it might shoot to hot unexpectedly.
- Engine Overheating: If the sensor fails to report that the engine is getting hot, the cooling fans may not turn on when they need to.
- Cooling Fans Run All The Time: A sensor that's stuck sending a "hot" signal can make the cooling fans run constantly, even when the engine is cold.
- Reduced Fuel Economy: The computer may think the engine is always cold and inject too much fuel, a condition known as running rich.
- Black Smoke from Exhaust (Diesel): For Cummins owners, a rich fuel mixture can result in black smoke coming from the tailpipe.
- Poor Engine Performance: Your truck might feel sluggish or go into a reduced power "limp mode" as the computer tries to protect the engine from what it thinks is a serious temperature problem.
No Recalls, But Quality Matters
As of early 2026, there are no active recalls or widespread Technical Service Bulletins (TSBs) from Ram for the engine coolant temperature sensor on 2016-2024 models. However, owner forums frequently mention that low-quality aftermarket sensors can be dead-on-arrival (DOA) or fail quickly. Choosing a reliable brand is important to avoid doing the job twice.
Choosing the Right Aftermarket ECT Sensor
You don't have to buy the OEM part, but for a critical sensor, it's wise to choose a quality aftermarket brand. They are often categorized into tiers based on quality and reputation.
- OEM-Tier Aftermarket (Excellent Choice): Brands like Delphi and NGK/NTK are often original equipment manufacturers for many car brands. Standard Ignition (SMP) is another highly respected brand known for quality electronics. These are your safest bets for a reliable, long-lasting repair.
- Reputable Aftermarket (Good Choice): Brands like Beck Arnley, Walker Products, and Holstein have a solid reputation. They focus on providing parts that meet or exceed OEM specifications and are a good balance of price and quality.
- Value Brands (Use with Caution): Brands such as Dorman, Four Seasons, and Global Parts offer attractive pricing. While Dorman offers a wide range of parts, their quality on sensors can be inconsistent according to owner feedback. These brands can be a budget-friendly option, but be aware of the potential for a shorter lifespan or incorrect readings. 🎬 See how to test your sensor using a basic multimeter.
Pro Tip: OEM vs. Aftermarket Cost
For the Ram 3500, the genuine Mopar or Cummins ECT sensor is often priced competitively with top-tier aftermarket options. It's worth checking the dealer price before you buy, as you might get an original part for the same price as a high-quality aftermarket one.
Typical Replacement Costs
The cost to replace the ECT sensor is reasonable, especially if you do it yourself. The part itself is not expensive, and labor is minimal on the Cummins engine.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Part | $17 - $62 |
| New OEM Part | $30 - $70 |
| Shop Labor | $60 - $180 |
| Total Professional Replacement | $90 - $242 |
Frequently Asked Questions
Where is the ECT sensor located on the Ram 3500?
The location depends on your engine. On the 6.7L Cummins, it is very accessible, typically located on the driver's side of the cylinder head near the thermostat housing. On the 6.4L Hemi, it is often located at the front of the engine block, sometimes under the A/C compressor, which can make it more difficult to reach.
Can I replace the Ram 3500 ECT sensor myself?
Yes, this is a very DIY-friendly job, especially on the 6.7L Cummins. The basic steps involve partially draining the coolant, unplugging the sensor, unscrewing it, installing the new one, and topping off the coolant. It usually requires only basic hand tools.
🎬 Watch this step-by-step walkthrough for replacing the sensor yourself.Is it the ECT sensor or the Coolant LEVEL sensor?
This is a common point of confusion. The ECT sensor reads temperature. The coolant level sensor is located in the bottom of the coolant reservoir (degas bottle) and triggers a "Low Coolant" message on the dash. If your temperature gauge is acting up, it's the ECT sensor. If you get a low coolant warning but the tank is full, it's likely the level sensor.
What happens if I ignore a bad ECT sensor?
Ignoring it is not recommended. You will likely suffer from poor fuel mileage and reduced engine power. The biggest risk is the engine overheating without you knowing it, as the sensor may not trigger the cooling fans or provide an accurate gauge reading, which can lead to severe and expensive engine damage.
Helpful Videos
Technical Specifications
OEM Part Numbers: 4954905 5149077AB 05149077AA 68045803AA 68060339AA
2-pin, plug-in thermistor sensor.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Ram 3500:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Is Your Ram 3500's Engine Acting Up? It Could Be The Coolant Temp Sensor
- Symptoms of a Bad ECT Sensor
- No Recalls, But Quality Matters
- Choosing the Right Aftermarket ECT Sensor
- Pro Tip: OEM vs. Aftermarket Cost
- Typical Replacement Costs
- Frequently Asked Questions
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