Assuming that all of your other instrument lights are working, you can start by testing the circuit that grounds the light. As Art mentions, the sources of the grounds are pin 22 of the ECU and pin 3 of the ICU, through a pink wire. That pink ground wire runs through pin 3 of the semi-circular connector that plugs into the back of the instrument cluster.

Put the ground side of a test light on that pin, and the other wire on a reliable 12v source, and turn to KP II - if the test light comes on, the circuitry to that point is okay, and the problem is more likely in the cluster circuits.