Fuel and temp gage

In the diagram, just to the left of the limiter is the multi pin connector. The connections there can go bad. You lose all your gauges and panel lights.

Panel grounds often go bad. But, if you can probe the circuit board where your diagram shows 5v and 12v , you will have your answer right away.

Solid state limiters are available on Ebay. They are about $40 to $50 dollars. Not cheap but, they do have a fail safe mode to protect the gauges. There are other sources on line.