"Dead gauge" is the short answer. Ohm meter at terminals ( marked on the back of the gauge ) A and S should show 20 ohms. Same applies to oil and temp' gauges except terminals are marked I and S.
I'll go ahead and clear the possible confusion before it begins.... Not all models have 20 ohm gauges. Majority are standard panels having oil warning lamp and 2 of 13 ohm gauges. Your rally panel has 3 of 20 ohm gauges. Hope this helps