Quick Answer
Yes, a blown fuse can cause the speedometer to stop working. The speedometer is an electrical component that requires power to operate. If the fuse that provides power to the speedometer blows, it will cause the speedometer to lose function.
What Causes a Speedometer to Stop Working?
There are a few common reasons a car’s speedometer may stop functioning properly:
- Blown fuse – Each electrical circuit in a vehicle has a fuse to protect it from power surges. If this fuse blows, it cuts off power to the speedometer.
- Faulty speed sensor – The speed sensor monitors the rotation of the vehicle’s transmission or wheels. If it malfunctions, it cannot send the correct speed data to the speedometer.
- Damaged speedometer cable – The speedometer cable connects the speed sensor to the speedometer unit. If this cable is damaged or disconnected, data cannot be transmitted.
- Faulty speedometer unit – The speedometer itself may have an internal failure in the gauges, wiring or electronics that prevents it from working properly.
- ECU failure – The engine control unit processes data from speed sensors. If it fails, the speedometer can malfunction.
Of these, a blown fuse is one of the most common reasons for a speedometer failure. Let’s look closer at how this can occur.
How Does a Blown Fuse Stop the Speedometer from Working?
Modern speedometers rely on electrical power to function. Older mechanical speedometers worked using physical cables connected to the transmission or wheels. But today’s speedometers get speed data from sensors that require electrical power.
This power is supplied through a circuit that is protected by a fuse. The fuse helps prevent electrical shorts or power surges from damaging the wiring or speedometer.
Speedometer Fuse Location
The fuse that powers the speedometer is most often located in the vehicle’s fuse box. This is usually found under the dashboard on the driver’s side of the passenger compartment. It may also be located in the engine bay fuse box in some vehicles.
Consult your owner’s manual to determine the specific location of the speedometer fuse for your make and model of vehicle. It will be labeled as “Speedometer”, “Instrument Cluster”, or something similar.
Blown Fuse Effect
When the speedometer fuse blows, it breaks the circuit that provides power to the speedometer unit. With no power, the speedometer will immediately stop registering vehicle speed. The speedometer needle may remain stuck at 0 mph or the last recorded speed.
Other dashboard instruments may also stop working when the speedometer fuse is blown, since multiple gauges are often on the same fuse. If your speedometer and other gauges suddenly stop at once, start by checking this fuse.
How to Diagnose and Replace a Blown Speedometer Fuse
Diagnosing and replacing a blown speedometer fuse is a straightforward repair you can do yourself in a few simple steps:
1. Locate the Fuse Box
Refer to your owner’s manual for the fuse box location. In most cars, it is below the steering column underneath the dashboard. The fuse box has a cover that you’ll need to remove to access the fuses.
2. Check the Speedometer Fuse
Examine the speedometer fuse in the fuse box. A working fuse will have an intact metal strip inside. A blown fuse will have a broken or melted metal strip. The plastic housing of the blown fuse may also appear damaged.
3. Remove the Blown Fuse
Pull the blown speedometer fuse straight out from the fuse box to remove it. Use needle-nose pliers if you’re having trouble gripping the small fuse.
4. Install a Replacement Fuse
Insert a new fuse of the same amperage into the empty slot in the fuse box. Make sure it clicks fully into place. Your owner’s manual can confirm the right fuse rating. Typical ratings are 5, 10 or 15 amps.
5. Test the Speedometer
Start the car and check if the speedometer is now working. Also check that any other dashboard gauges that were not working are now functioning again.
What to Do if Replacing the Fuse Doesn’t Fix the Speedometer
If installing a new speedometer fuse does not restore operation, there is likely a larger electrical issue at play. Here are some steps to take:
– Inspect wires and connections around the fuse box and speedometer for damage. Shorted or disconnected wires can blow fuses.
– Make sure the fuse you installed is the correct amperage. Using too high of a fuse rating bypasses protection.
– Test voltage to the speedometer with a multimeter when the key is on. No power indicates a wiring issue.
– Have your vehicle’s speed sensor and wiring professionally inspected and tested.
– As a last resort, the speedometer unit itself may need replacement if found to be faulty.
Getting stranded because your speedometer died may be inconvenient, but in most cases it’s an easy fix. So don’t panic, just replace the blown fuse and get back up to speed!
Frequently Asked Questions about Speedometers Not Working
Why did my speedometer suddenly stop working while driving?
The most common cause of a speedometer failing without warning is a blown fuse. Fuses provide electrical protection and can blow due to power fluctuations, shorts, or normal wear over time. Always check the speedometer fuse first if your gauge stops working.
Can a speed sensor cause the speedometer to not work properly?
Yes, a faulty vehicle speed sensor is a common reason for speedometer malfunction. The sensor monitors the rotation of the transmission or wheels to determine speed. If it fails, incorrect or no data will be sent to the speedometer.
Is it safe to drive with the speedometer not working?
It is not recommended to drive with an inoperable speedometer, as you have no precise measurement of your vehicle’s speed. This makes following posted speed limits difficult and could present a safety hazard. At minimum, get the speedometer repaired as soon as possible.
What if my digital speedometer display is not working?
On modern vehicles with digital speedometer displays, the same potential issues can occur. Check for a blown fuse, inspect speed sensor and wiring condition, and have the speedometer gauge unit tested. Electronics in the display may have failed.
How much does it cost to fix a speedometer that stopped working?
Replacing just a blown fuse that caused the speedometer malfunction will only cost a few dollars. If other components need repair, it can range from $100 for a speed sensor, to $500 or more if the entire instrument cluster requires replacement.
Key Takeaways about Blown Fuses and Speedometer Failure
– A blown fuse that provides power to the speedometer is one of the top reasons for its failure.
– Locate the speedometer fuse using your owner’s manual and check for an intact filament inside.
– Blown fuses must be fully removed before inserting a same-amperage replacement fuse.
– If replacing the fuse does not restore speedometer function, there may be an electrical issue needing repair.
– Never drive without a working speedometer, as you cannot verify your vehicle’s speed.
– Speed sensors, wiring damage, and gauge failures can also cause speedometer malfunction.
Conclusion
In summary, a blown fuse is a very common and fixable reason that your car’s speedometer can suddenly stop working. Always start diagnosis by checking the speedometer fuse in the fuse box. Replace any blown fuses with new ones of the same amperage rating. This should restore power and operation in most cases. Driving without a functioning speedometer is hazardous, so get any underlying electrical faults repaired quickly to keep your gauge working properly. With basic fuse inspection and replacement, your speed readout will be up and running again in no time.
