'70 Sport Satellite. All exterior lights work but my dash is dead. No fuel gauge, no temp gauge, no idiot lights, no high beam indicator, no turn light indicators. What is causing this? I assume a ground issue or maybe the voltage limiter?

Wipers don't work either but I assume that's another problem...

start with checking the round black bakelite connector that plugs on the pins on the dash printed circuit

It has to have a good ground are it will never work. If you have redone the dash you will have to fix it where it will get a ground.

I checked the round connector in the back, no visible issues. Where is the ground for the dash/gauge assembly?

The screws holding it in are the ground. So you need to be sure the area around the screw has no paint on it.

Sounds like a burnt amp guage to me. Check your firewall multi connector where the fusible link goes in for voltage.If you have it going in, then check out a wiring diagram in a manual and see which connector the voltage comes out from the dash and check that. If you have no volts coming out you're amp guage is probably burned or the voltage regulator on the dash panel is burned. Check out Mopar Action tech questions for more details.

with a jumper wire with alligator clips on each end, ground the metal dash frame & see what happens. If nothing might need to drop the column a bit so you can take out the cluster (drape a rag on the col to protect it) & see if the round connector has fire to the pins but I imagine it does then see why (where) the printed circuit copper strips are not grounding to the dash frame and or why the dash frame is not grounding to the rest of the car body