What is wrong with a 1992 Lincoln town car whose odometer work but the speedometer does?

If the odometer works but the speedometer doesn't on a 1992 Lincoln Town Car, the problem almost certainly lies within the speed sensor or its associated wiring. The odometer and speedometer both get their speed information from the same source. Since the odometer works, it's less likely to be a complete failure of the instrument cluster itself.

Possible causes include:

* Faulty Vehicle Speed Sensor (VSS): This sensor is usually located on the transmission and sends a signal to the instrument cluster. It's the most common culprit.

* Damaged wiring between the VSS and the instrument cluster: A broken wire, short circuit, or corroded connection can interrupt the signal.

* Problem with the instrument cluster itself (less likely): Although the odometer works, a problem within the speedometer component of the instrument cluster is still possible, though less likely given the odometer's functionality.

* Gear in the transmission: In rare cases, a damaged gear within the transmission that drives the VSS could interfere with the signal.

A mechanic would need to diagnose the specific issue by testing the VSS, its wiring, and potentially the instrument cluster itself.