Why is my 2002 Ford Ranger speedometer not working?

The most common reason You'd see the speedometer not working on a 2002 Ford Ranger is because the vehicle speed sensor (VSS) has failed, though in much rare circumstances it can also be caused by a bad engine control unit (ECU). Replacement costs for a VSSRun about $10 to $30, depending on the brand You purchase, so it's not a very expensive part, nor is it that hard to switch out: It's held in place by two bolts and has just one engine wiring pigtail connected to it. Now, obviously, the speedometer itself can also fail, but if You have this, You'll likely see other gauges in the instrument panel failing to function in tandem, so that's going to be an obvious sign there. If You've got a check engine light (CEL) on, there'll be a diagnostic trouble code (DTC) that can help You narrow down what's going on with Your speedometer.