More Electrical Help ...

Everything one these old cars relies on nut and bolt metal to metal for ground path. Inst' panel is no exception. If it isn't screwed to the dash, the lighting, etc., will not work.
A aftermarket replacement headlight switch will also have a terminal for ground wire that OEM switch does not have. Adding these ground wires is not absolutely necessary but... if the switch is mounted in the same metal housing the added wire provides additional ground path to entire metal housing.
Temp gauge pegged to H has often been that purple sender wire pinched under a valve cover or otherwise shorted to ground in engine bay. Fuel gauge needle moves only from home to E at switch on has often been saturated float.
I would take the inst' panel to the workbench. A 12 volt power supply will test all lighting. A 3 volt battery/power supply will test fuel and temp gauges to about 1/2 their range. If it all works at workbench it should work in the vehicle.
Your gauge voltage limiter? I don't know if 62 had the plugged in can type. It might be in the fuel gauge or in the temp gauge. If it is in a gauge that gauge will have 3 posts.
We'll assume it is working because the gauges are working.
While the inst' panel is out of the car, temp gauge is purple wire, fuel gauge is dark blue. Check ohms signal from senders on both these. 80 is fuel E and temp C , 10 is fuel F and temp H.