VSS Odometer works/ Speedo does not??? 1991 Jeep Comanche 4.0

Pulled my VSS out and attached it to a drill, just like when I drive down the road my speedometer is not working but the odometer still works as it should. Its only a 2 wire sensor, possible one side is for odometer the other for speedometer???? Hoping its not my gauge cluster. Any help is appreciated before I go to NAPA and spend another $43 on a sensor just to find out its the head.

This is in a 1991 Jeep Comanche

Thanks, Adam

Sorry but sounds like gauge to me, the VSS just has a signal and ground wire. Does yours not have a cable-driven speedo/odometer and the VSS is just for the pcm anyways? MJ isn't a flavor I've owned...

definitely the speedo head.

Sometimes its better to be lucky than good. One good tap on the dash and guess what, it works! Sweet