2003 galant speedometer stops randomly while driving at different speeds

Hi. This happens on my wife's car also. Was not speed sensor but speedometer gauge itself. Unfortunately you may have to replace the instrument cluster itself unless you are mechanically inclined to find one at the junk yard (which they will pull for you)and do yourself, its a lot cheaper than dealer. Its not very complicated just a few screws and a couple plugs on the back. I did this with a speedo at the junk yard only I took it apart and only used speedo itself since all my other gauges were known to be good. Next time you are driving and it goes out hit on the dash to see if it then moves but would still suspect its faulty either way.

Many 'inexpensive' OBD 2 code readers have live data .. Find a friend that has one .. Connect it to the vehicle and go for a test drive.. When speedometer stops working, see IF the code readers live data shows same thing .. IF it does, problem is in the signal TO the cluster... Guessing at it can be costly!