Yes, the switch progressively brightens the IP lighting as you turn it, and at max position, turns on the dome light(s).
At minimum position, instrument lighting will be very low or essentially off.
If there's not much change in IP illumination, it's likely to be the normal corrosion of contact mechanism.
Those thumbwheels have been prone to poor dimming operation for decades.
IIRC, there are repops available for Charger Rally cluster, but it could just need cleaning.
Maybe try squirting some aerosol contact cleaner in there.
