The odometer fuse in a car is one of several fuses protecting the electronic components of the vehicle. As with any other type of fuse, the odometer fuse is designed to break if exposed to a stronger current than is safe for the odometer. If this happens, the odometer and any connected components are protected from damage but are not functional until the fuse is replaced.
When small electronic components in a car, such as the odometer, speedometer, lights, or windshield wipers, stop working, it is often due to a burnt-out fuse. Fuses vary based on the size and type of the car, and their setup varies as well. Most fuse boxes are accessible from within the cars and can usually be opened by hand or with a screwdriver. The fuse box contains all of the fuses for the car, each of which may be wired to one or more of the electrical components. Because the fuses are only used for electronics, any car with an analogue odometer does not have an odometer fuse.
The location of the fuse box as well as the purpose of each fuse is listed in the owner's manual of the car. When replacing a fuse, it is very important to use an identical fuse, matching the size, type and amperage. A fuse that fits but does not have the proper amperage can either burn out immediately or allow too much electricity to reach the connected component.