Gas gauge always full (1968 Barracuda)

Gas gauge always full (1968 Barracuda)

Hi folks,

I've got a 68 Barracuda with some gauge issues:

Gas: Rises to full when key turns on, slowly falls to empty when key turns off
Temp: Always stays at C indicator
Oil Pressure: Always stays at low indication
Alternator: Always stays in the middle

I'd like to get the gas gauge working (got aftermarket gauges for the rest).

After poking around this forum, I suspect this is likely either a bad voltage limiter or possibly a short to ground between the sending unit and the gas gauge (as RedFish suggested here).

Before I order a new voltage limiter and figure out how to pull the gauge cluster, does anyone know how I could rule out a short to ground or other issues?