no gas gauge or temp gage

65 Barracuda - reawakening after 20+ yrs. of a driveway snooze. HERE is the LAST of the non functioning electrical issues.: No gas or temp gages working.

Grounded out both: no gage movement on either.... assuming both can be tested the same way...

SO...conventional wisdom would say its the voltage limiter. I removed it, cleaned the "legs". put 12v into leg. 1, and get ~ 6 volts out of the center leg. seems good, right?

SO: i cleaned all the traces and checked the leg socket to the gauge posts for continuity....all good.

SO: I figure both gauges are bad......but it would seem that that is unlikely.

SO: I removed the gage cluster......again......:

Question: with just the 2 posts; how can I check gauge functionality without burning them up?
TIA