Why wont my speed odometer work on my 2002 dodge neon rt????please help

The speedometer is driven by the computer which uses the Vehicle Speed Sensor, which is located on the transmission, to determine how fast the vehicle is traveling. It is not uncommon for the VSS to go out unexpectedly, usually the check engine light will come on when it malfunctions, and the computer will lock the transmission in 2nd gear, which will allow you to limp the car in to a repair shop.

Speedometer works on a cable that goes from the transmission to the instrument cluster , trans spins cable , cable spins speedometer , if cable is disconected at either end , or broken , it won't work. If anyone you know is handy with cars , ask them to find the speedo cable and check each end.