Looking for someone who has who has installed a different gauge cluster

No, yellow in the dome light circuit is the switch to ground. So I'm sure THAT is something to think about.

The dome lights get power all the time, "hot." The dome lights are NOT grounded. Look at one. They have two terminals, both insulated. All the switches, the doors, and the headlight switch, which turn on the dome lights go to GROUND when activated.

So the circuit path is battery ----- fuse panel (fuse) -- power to light(s)-- yellow coming off second lamp(s) terminal -- branches off and goes to all door switches and to headlight "dome" switch.

Now the gauge lights. No not the tan. This is another "trick"

The headlight switch GETS power from two sources. The big black no 12 going to "b1" ONLY runs the headlights, nothing else

Everything else, the tail, the park, and dash, gets power from "B2" which comes from the tail light fuse

This power feeds TO the dimmer control, comes OUT of the dimmer control on the tan, and (here's the trick)

This tan feeds dimmer controlled power TO the instrument fuse. This power goes THROUGH the fuse, and on the other side of it changes to ORANGE. These orange wires then feed off to all the dash lamps. You should already have an orange which would have gone to the round cluster connector.