There are several things that can cause your 2003 Mitsubishi Gallant speedometer not to work. The most common cause is a malfunctioning speedometer cable.
The speedometer doesn't work. It doesn't respond to the speed we are going.
Output speed sensor
It is probably the speed sensor. It is located on the transmission and sends an electrical signal to the speedometer.
broken cable? Broken gear at transmission end? Broken gear at speedometer head?
Do you have check engine light? If not you have an electrical problem within the speedometer assembly.
the speedometer in my 2004 Montana kept sticking. showing I was going 50mph when I was sitting still. the instrument cluster turned out to be at fault and had to replace the entire cluster as it is one unit.
It's probably a fuse. Take it to the dealership.
There are several things that can cause your speedometer to stop working. The most common cause is a blown fuse. The second most common cause is a malfunctioning speedometer cable.
If both the speedometer and odometer are not working I would suspect the VSS (Vehicle Speed Sensor) is at fault. If the speedometer doesn't work and the odometer does, I would suspect the instrument cluster is at fault.
Cruise will NOT work if the speedometer has a problem
Its either a faulty cable or a faulty electrical connection.