Fuel and temp gage

If I recall correctly, the fuel and coolant temp. gauge use the same plug-in limiter. And you have a Red light for oil pressure?
Of course , check the fuse, I think it is for just those 2 gauges.
Do the dash panel lights work? It's a different fuse but, I think it's just one large connector to supply all the gauges and lights. Plugs into the circuit board.

Access is not easy with the instrument panel installed but if you can lay under the dash and probe the 12v input to the Limiter and the pulsating output with a light that will confirm the problem. (without shorting anything out).
An analog voltmeter will show about 5v output. Not sure what an electronic digital meter will show. The display may be erratic??
Just in case you don't know. The Limiter takes 12 volt input, and an internal mechanical contacts open and close rapidly. 12v-0v-12v-0v........ The result is a nominal 5v that the gauges "see".