My first guess would be the rear axle speed sensor since this is a known problem with Dodge Trucks. When mine went out the speedometer would work, but not until you hit about 25 mph or so. Also it cause the ABS light to stay on. It's an easy fix. About 36 bucks for the part at the dealer and takes about 10 minutes to change out. It's located top center just to the front side of the rear axle. Just unplug the wires, unscrew the bracket and pull the old one out. Reverse the process to install the new one.
you can go to speedometer and out of speedometer
If the abs light is on, then you might have a rear axle speed sensor issue. If not, then you have a cluster problem.
check speedometer cable for possible disconnection; it comes out of firewall and goes to transmission
the abs sensor located in the rear end housing
The odometer has failed.
The speedometer and odometer are electrically operated. There is no mechanical connection to the drivetrain. If there is no power, they don't work.
Have the ABS checked for coedes, the rear sensor might have failed.
Start with checking the fuses.
If the speedometer is not working but the odometer is, I would suspect the dash cluster is at fault. If both speedometer and odometer are not working I would suspect the speed sensor on the transmission is at fault.
If the speedometer and the odometer are not working, I would suspect the VSS (vehicle speed sensor). If only the speedometer is not working I would suspect the instrument cluster has problems.
The speed sensor needs replaced. It is on the trans.
why would a speedometer stop working on a Mazda