Voltage limiter

"What the deal is" and I know not why, it seems pretty silly, Ma built the thing right into the fuel gauge. What this means is, the gauge has THREE terminals

1 is switched 12V INTO the IVR

1 is the sender for the fuel gauge

1 is the regulated OUT of the IVR which is internally fed to the fuel gauge, and fed OUT this stud to the temp and oil gauges

Generally "if you are able" you need to surgically disconnect the IVR internally without damaging the gauge, then "saddle" a conventional external one onto the dash, and wire it's in/ out to the appropriate gauge studs. Be sure it's grounded.

Also pay attention to other possible cluster troubles while you have it out

Add a ground pigtail which you can bolt to the column support

Loosen / tighten all the gauge nuts or better yet replace the "fake" nuts with real ones

Clean and service the lighting

Inspect and electrically inspect the cluster connector pins. These often give guys trouble, and must be soldered to the board traces.