Here are the most likely reasons why the odometer stopped working while the speedometer continues to function:
* Odometer Gear/Mechanism Failure (Mechanical Odometers): Older vehicles, even some 2001 models, might still have a mechanical odometer component driven by a cable connected to the transmission. A broken gear, worn cable, or a malfunctioning component within the odometer itself could prevent it from registering mileage. This is less likely on a 2001 Ram, but possible if it has a partially mechanical system.
* PCM/Instrument Cluster Issue (Electronic Odometers): Most likely in a 2001 Ram, the odometer is electronically controlled. The problem might lie within:
* Instrument Cluster: A faulty circuit board, a damaged solder connection, or a failing odometer display component within the instrument cluster itself could prevent the odometer from displaying the data it receives.
* Power Control Module (PCM): The PCM receives the speed signal and processes it; a problem within the PCM's odometer calculation function could prevent the correct information from reaching the instrument cluster. This is less common, as a PCM failure usually causes more widespread problems.
* Wiring/Connections: A break or short in the wiring between the PCM and the instrument cluster could interrupt the odometer signal.
* Rare: Faulty Speed Sensor Signal Processing: While the speedometer is working, there might be a subtle problem with the signal's processing specifically for the odometer function within either the PCM or instrument cluster. This is less probable given the speedometer is functional.
Troubleshooting Steps (in order of easiest to hardest):
1. Check Fuses: Start with the simplest check – make sure all relevant fuses related to the instrument cluster are not blown.
2. Inspect Instrument Cluster Connections: Carefully examine all the connectors and wiring going to the instrument cluster. Look for loose connections, corrosion, or broken wires.
3. Consult a Repair Manual: A repair manual specific to your 2001 Dodge Ram 1500 will provide wiring diagrams and troubleshooting steps for the instrument cluster and PCM.
4. Professional Diagnosis: If you can't find the issue yourself, take the vehicle to a mechanic or an automotive electrician. They have diagnostic tools that can scan for codes and pinpoint the problem more accurately. They may need to test the instrument cluster and/or the PCM.
In short, the most likely culprits are a problem within the instrument cluster itself or, less likely, a specific processing failure within the PCM related to the odometer function. Since the speedometer works, it rules out the most obvious – a faulty VSS.
