Snowmobile Speedometer Not Working (12 Causes)

Snowmobiling is an exhilarating winter activity. However, encountering issues with your speedometer can turn it into a frustrating experience. Determining the culprit entails a systematic approach to pinpointing the problem.

Here are 12 causes of snowmobile speedometer not working:

1. Faulty Speedometer Cable
2. Defective Magnet or Speed Sensor
3. Compromised Electrical Connections
4. Wiring or Circuit Board Issues
5. Gear and Teeth Problems
6. EMI and Software Glitches
7. Driveline Gear Key Malfunction
8. Gear Adapter Failure
9. Compromised Instrument Cluster
10. Snow or Ice Buildup
11. Vibration and Impact
12. Broken Driveshaft

While this list is non-exhaustive, it provides many factors that result in a malfunctioning speedometer. In addition to this guide, check out my other posts below for more information:

• Vehicle speedometers not working
• Tips for fixing a snowmobile speedometer

Snowmobile Speedometer Not Working – 12 Causes

1. Faulty Speedometer Cable

Cable condition is critical, especially for analog-mechanical speedos. Speedometer cables are responsible for transmitting crucial data on rotational driveshaft speed, allowing the needle or digital display to indicate the speed of the machine.

However, factors like wear, contaminants, loose connections, and surface damage (to name a few) can compromise their integrity. When this happens, there is no chance the speedometer will work.

2. Defective Magnet or Speed Sensor

The magnet and speed sensor (view on Amazon) are vital for measuring transmission rotation and relaying relevant information to the ECU. When faulty, they yield inaccurate readings and disrupt fuel flow regulation, ignition timing, transmission shifting, and cruise control (among others) — consequently triggering the Check Engine Light.

Several factors can lead to a defective magnet or speed sensor. However, the most prevalent causes behind their deterioration are physical damage, moisture/water exposure, and wear and tear. If you are searching for an easy fix, you may want to add speed sensor misalignment to this list.

Physical damage disrupts the speed sensor’s ability to generate accurate signals. Water ingress leads to corrosion, short circuits, and electrical malfunctions. Lastly, normal wear and tear from continuous use, vibrations, and exposure to various weather conditions adversely affect these components’ performance (not to mention contribute to the degradation).

3. Compromised Electrical Connections

If neither the sensors nor cables are responsible, consider the electrical connections associated with your speedometer. These connections may be corroded, disrupting the flow of electrical signals to and from components, or they may come loose. While at it, keep your eyes peeled for power shortage or overload, electrical imbalances, and a weak or failing battery (view on Amazon).

Corrosion in electrical connections can result from exposure to moisture, dirt, and debris, among other factors. Meanwhile, looseness is brought about by vibrations and usage of the snowmobile.

Fortunately, prevention is straightforward and entails regular inspection and cleaning of the connections — applying dielectric grease or corrosion inhibitors for protection against rust and untimely breakage.

Synchronously, examine speed sensor wirings and those linking the speedometer to the ECU. Typically, an interrupted electrical circuit is found in these wirings, leading to damage or disconnection.

Regardless of the cause, address faulty wiring promptly to prevent signal breaks between components, which can lead to more critical transmission shifting issues.

4. Wiring or Circuit Board Issues

Damaged or interrupted electrical circuits in speed sensor wirings or connections to the ECU can result in incorrect readouts and intermittent speedometer function. In like manner, the circuit board processing electronic signals may sustain damage due to physical impact or exposure to extreme temperatures and yield similar results.

That said, it is essential to promptly address faults relating to these components to prevent signal breaks affecting speed data transmission. Prevention-wise, you can safeguard speed sensor circuits from damage by ensuring proper installation and zero rodent infestation. As for the circuit board, observing safe driving habits and stringent upkeep practices does the trick.

5. Gear and Teeth Problems

A snowmobile speedometer is typically connected to a speed sensor, which detects the rotational speed of a component in the drivetrain. If there are problems with gears and teeth in critical components, this may result in the speed sensor hindering accurate signal transmission to the speedometer. Hence, worn or missing teeth can lead to inconsistent speed readings or a complete failure of the speedometer.

6. EMI and Software Glitches

Modern speedometers, like LCD and smartphone-integrated types, use signals and software for data processing. However, electromagnetic interference (EMI) or bugs can disrupt the speed sensor and the speedometer’s communication. This disruption, in turn, can lead to inaccurate readings or a complete failure of the unit.

There are many causes behind these interferences other than EMI and software glitches. These include poor wiring and grounding, faulty connectors, component malfunctions, environmental factors, voltage fluctuations, and radio frequency interference (RFI) from nearby devices. Fortunately, these can be prevented through regular upkeep, secure connections, and shielding techniques.

7. Driveline Gear Key Malfunction

Especially if your snowmachine is secondhand, verify whether aftermarket upgrades had been done on the sled (bearing replacements, for instance). Determine this information at the point of sale, with inspection of the bearings immediately following suit. The reason is that a previous owner may have replaced the bearing without checking if the snowmobile has a shear key that needs tending to.

Post-sale add-ons aside, the gear adapter’s stock wire key can shear, halting driveline rotation and commonly causing speedometer failure. This failure is often linked to a bearing issue at the driveline’s PTO end. If the bearing fails, it can harm the gear adapter, ceasing speedometer functionality. In this situation, early issue detection acts as a warning for impending driveline-bearing failure.

The longevity of snowmobile speedometers varies based on the sled’s make and model. Some endure without bearing problems, while others may face challenges. Therefore, a good rule of thumb for safeguarding its life cycle is changing the bearing every 3000 miles or when the speedometer quits (whichever comes first) — ensuring they are always replaced in pairs.

8. Gear Adapter Failure

Due to the gear adapter’s integral role in translating mechanical movement to electrical signals, it can disrupt the accurate measurement of speed when it malfunctions. Subsequently, this leads to incorrect readouts.

Because of this disconnect between the transmission system and the speedometer, the latter cannot receive the necessary input to display the correct speed — rendering it ineffective.

9. Compromised Instrument Cluster

A compromised instrument cluster can render the speedometer inoperative by disrupting the overall functionality of its speed measurement system. Because it houses the speedometer and other indicators, its dependency on various interconnected components makes it vulnerable to the slightest irregularities with sensors, wiring, and even the speedometer itself.

In particular, an impaired cluster loses its ability to monitor and display various snowmobile parameters — speed data included. Naturally, nuances between different snowmobile speedometer types exist but lie in their specific design, technology, and components.

The instrument cluster may act a certain way depending on whether you have an analog-mechanical variant or one that employs digital sensors and electronic displays.

10. Snow or Ice Buildup

Although snowmobiles are built for cold-weather riding, the machine is not impervious to the elements. Snow can accumulate on the speedometer’s exterior or components, interfering with its sensors, mechanical parts, and electrical connections.

Having an obstructed view of your display will be the least of your concerns in these situations. The most common issue befalling sled enthusiasts is frozen precipitation penetrating gaps or openings in the speedometer casing — leading to internal moisture buildup that compromises electronic components most of the time.

Speed sensors, wires, and connectors are also detrimentally impacted by snow accumulation — resulting in erratic speed readings or a complete failure to display any speed information.

11. Vibration and Impact

Sensitive speedometer components like sensors, wiring, and the display mechanism may be susceptible to damage or disruption when exposed to excessive shuddering or impacts.

Vibrations from rough terrain, jumps, or collisions can lead to dislodgment, loosening, or breakage of internal connections. These outcomes could result in inaccurate readings, impaired functionality, or complete speedometer failure.

12. Broken Driveshaft

The driveshaft (view on Amazon) is vital for transferring rotational power from the engine to the track, enabling snowmobile movement. Crucially, the speedometer depends on the driveshaft’s rotational speed to calculate and display the snowmobile speed.

If the driveshaft breaks, it hinders this motion transmission, depriving the speedometer of input. As a result, the latter may show inaccurate readings or remain non-functional until the driveshaft is repaired or replaced.

Some pre-1999 model years of some snowmobiles have different part numbers for the covers and bearings. If you own such a unit, check to see if the bearing holders may be the wrong size.

Inspecting this is crucial since the difference in size between the hole and the bearing holder is always moved to the rear of the hole. This makes the track shift back on that side, making the driveshaft crooked.

Conclusion — Snowmobile Speedometer Not Working

If your snowmobile speedometer is currently not working, consider yourself fortunate. You now have an excellent opportunity to put what you learned from this guide and your skills to the test!

I specifically created this post to help bolster your mechanical savvy and confidence. But if you still feel unsure of tackling the task yourself, there is nothing wrong with seeking help from a reputable auto shop or certified technician.