The contacts between the speedometer head and the wiring connector need to be cleaned. If that does not work get a used speedometer. It fixed mine.
Is the TCM working normally and throwing no codes?
Check your fuses before anything else. Easiest and cheapest fix.
Since you replaced the sensor, and the speedometer still isn't working it is possible that you will need to replace the speedometer cable. Check the cable first to be sure that it is still properly connected, and if so replace the cable to see if that solves the problem.
its is you tachnometer that needs to be reseated or replaced.
May have replaced the wrong sensor or you have a bad wire in that curcuit. gm Jim
Have your mechanic check the speedometer cable connections. They no longer use a cable. It is electronic. If the speedometer is not working but the odometer is, the problem is in the dash cluster. If both the speedometer and odometer are not working, the speed sensor in the transmission may be at fault.
Either your VSS (vehicle speed sensor) or your GEM Module (generic electronic module) is not working/broke.
A 98 Civic does not have a speedometer cable. It is an electronic speedometer. So if you are having problems with it not working the most likely culprit is the vehicle speed sensor (VSS).
If the speedometer works, but the odometer is not working, there could be a fuse blown if the odometer is digital. If the odometer is not digital, then a gear is broken in the speedometer cable. It should be replaced.
the dashboard cluster could have broken. That happened to my 2004 trailblazer and I had to get it replaced
If the speedometer continues to work - probably a broken gear etc. in speedometer head and probably will have to be replaced. If speedometer does not work -- probably a broken speedometer cable
Call the dealer, and ask for the different kinds of speedometer gears, you'll be lucky if you can still get one. They Usually go by color and teeth count. If I remember right, they are the typical cause.