Where is the coolant temperature sensor on a 2001 Dodge Ram 1500?
The coolant temperature sensor (ECT) isn’t in a single fixed spot on all 2001 Ram 1500s; the location depends on the engine type. In most cases, the 4.7L V8 places the sensor in or near the thermostat housing at the front of the engine, while the 5.2L/5.9L Magnum engines usually mount the sensor on the cylinder head near the thermostat. Some 3.9L V6 variants follow a similar front‑of‑engine path. Use this as a guide to locate the sensor on your specific motor.
This article explains the typical placements for the common engines in that year, how to identify the sensor, and what to do if you can’t find it right away.
Engine variants and sensor placements
Below are the typical coolant temperature sensor locations for the common engines found in the 2001 Ram 1500. The exact position can vary by truck production date and options, so use these as reference points and look for a small sensor with a two‑wire (or sometimes three‑wire) connector threaded into a coolant passage.
- 4.7L V8 – Located at the front of the engine, on the passenger side near the thermostat housing. The sensor is screwed into the engine block/water jacket in that area and is usually easy to reach from the top of the engine.
- 5.2L Magnum (318) / 5.9L Magnum (360) – Typically mounted on the cylinder head on the passenger side, close to the thermostat housing or coolant inlet. Access can vary, but it’s generally on the side of the engine rather than the very front.
- 3.9L V6 – In many 3.9 configurations, the ECT sits near the front of the engine where the coolant jacket is accessible, often on the passenger side near the thermostat area.
If your truck uses a variant not listed here or the sensor isn’t visible in these spots, consult the factory service manual or a Dodge dealer for the exact location for your VIN and engine code. The sensor is small, threaded into a coolant passage, and typically has a two-wire harness feeding into the PCM.
How to locate and verify the sensor
Use these steps to locate the sensor on your specific Ram 1500 and verify it’s the correct part before replacement.
- Ensure the engine is cool and disconnect the negative battery terminal to avoid shorts while working near the cooling system.
- Open the hood and trace the wiring harness from the PCM toward the front and sides of the engine. The ECT will have a two‑wire (or occasionally three‑wire) connector that leads to a small sensor screwed into a coolant passage.
- Check the engine side where the thermostat housing or water jacket is located. Look for a small metal or plastic sensor with threads and a nearby coolant hose or fitting.
- Confirm by engine code: if you know your engine option (4.7L, 5.2L/5.9L, or 3.9L), compare the described locations to your truck’s layout to pinpoint the sensor more quickly.
- Tip: If you’re replacing the sensor, unplug the harness first, then carefully unscrew the sensor with a proper socket, and install the new part with sealant as required by the service manual.
After following these steps, you should be able to locate the coolant temperature sensor, test its function with a scanner or multimeter, and replace it if readings indicate a fault.
Summary
On a 2001 Dodge Ram 1500, the coolant temperature sensor location depends on the engine. The 4.7L V8 usually places the sensor at the front of the engine near the thermostat housing, while the 5.2L/5.9L Magnum engines typically mount the sensor on the cylinder head close to the thermostat. If you can’t find it in these areas, refer to the service manual for your exact engine code or ask a technician. Correct placement is key to accurate temperature readings and proper engine management.
What are symptoms of a bad coolant temperature sensor?
Symptoms of a bad coolant temperature sensor include an erratic temperature gauge, engine overheating, illuminated check engine light, poor fuel economy, and a rough idle or stalling. Other signs can be the cooling fan not working correctly, black smoke from the exhaust, and difficulty starting the engine.
Performance and operational symptoms
- Engine overheating: The most critical symptom, as the sensor failing can prevent the engine from properly engaging the cooling fan.
- Erratic temperature gauge: The needle may show a constantly high, low, or fluctuating temperature.
- Rough idle and stalling: The engine's computer uses the sensor's data to calculate the right air-fuel mixture. An incorrect reading can cause the engine to run poorly, idle roughly, or stall, especially when cold.
- Poor fuel economy: The car may use more fuel than it should because the engine computer is getting incorrect information about engine temperature and is adjusting the air-fuel mixture incorrectly.
- Difficulty starting: The engine may be hard to start, especially when warm, due to the wrong amount of fuel being injected.
Exhaust and emissions symptoms
- Black smoke from exhaust: This indicates the engine is running too rich (too much fuel), which can be caused by the sensor sending a faulty "cold" signal.
- Increased emissions: The incorrect air-fuel mixture can lead to higher emissions, potentially causing your car to fail an emissions test.
Other warning signs
- Check engine light: The engine control unit (ECU) will trigger the light if it detects a problem with the sensor's data.
- Cooling fan malfunction: The radiator fan may not turn on when the engine gets hot, or it may run constantly.
- Poor engine performance: You may experience reduced power, misfires, or engine pinging.
Where is a coolant temperature sensor located on a 5.7 Hemi?
The 5.7 Hemi coolant temperature sensor is located on or near the thermostat housing on the engine block. It is a single-wire sensor that screws into the housing and is connected to the engine's computer.
This video shows the coolant temperature sensor on a Dodge Ram 1500 5.7 engine: 58sLara's GarageYouTube · Mar 18, 2024
- Location: The sensor is situated on the engine block, where the thermostat is housed. You can find it near the upper radiator hose.
- Identification: The sensor is a single-wire component that screws into the thermostat housing. You can verify you've found the correct one by comparing it to the replacement part you purchased.
- Replacement: Before starting, allow the engine to cool down completely and disconnect the negative battery terminal for safety. A 19mm socket or wrench is often needed to remove the sensor, and some coolant may leak out during replacement, so keep a rag or drain pan handy.
Where is the coolant temperature sensor located?
The engine coolant temperature sensor is typically located near the thermostat housing, at the front of the engine where the upper radiator hose connects. It screws into a metal port on the engine block, cylinder head, or water pump housing and can be identified by the electrical connector attached to it.
This video shows the location of the engine coolant temperature sensor on a specific car model: 55sRed Pill GarageYouTube · Feb 19, 2022
Common locations
- Thermostat housing: This is the most common location, found at the front of the engine where the top radiator hose connects to the engine.
- Cylinder head: In some cases, the sensor may be screwed directly into a cylinder head.
- Water pump housing: It can also be located on or near the water pump housing.
- Coolant crossover pipe: On some engines, like those with a V-shaped cylinder configuration, the sensor might be on a crossover pipe under the intake manifold.
You can watch this video to see a close-up of the coolant temperature sensor in place: 41srichpin06aYouTube · May 8, 2021
How to find it
- Follow the top radiator hose: The easiest way to find the sensor is to locate the upper radiator hose and follow it to where it enters the engine. The sensor is usually nearby.
- Look for the electrical connector: The sensor is distinguished by a wire harness connector plugged into it.
- Check your repair manual: If you're having trouble finding it, consult your vehicle's repair manual for a diagram of your specific engine.
- Do a quick online image search: Searching for "engine coolant temperature sensor location" along with your car's make and model can provide a specific visual reference.
Where is the temperature sensor on a Dodge Ram 1500?
The coolant temperature sensor on the 2020 Ram 1500 Bighorn is typically located near the thermostat housing on the engine block.
