Just replaced the starter in my elderly mother's car. That went easy enough albeit longer than expected due to bad new part needing to be taken back to be replaced. Car started fine, reset the alarm code, it ran fine during testing (but I didn't look at the speedometer then), mother drove it to church and apparently now the speedometer doesn't work. It'll move up to below the 0mph mark at startup but won't move beyond that no matter what the speed.

BUT.. (and here's where it gets puzzling). the odometer works fine, the trip meters work fine, the cruise control works fine, all the dash lights work, there are no check engine or error codes showing, the D3 & D4 lights don't blink indicating a problem, the car shifts smoothly at a variety of speeds (auto trans) and so far (tho I haven't pulled all of them yet to eyeball each one of them) the majority of fuses are fine. It does not seem to fit a VSS problem from all I've researched. Other than the speedometer not moving, it has no indications that there are any problems at all.

Does anyone have any ideas of what it could be?? Many thanks to anyone that can help her safely get back out on the road!