if you don't have BRAKE AND OIL ( if oil is not a gauge )on cluster at RUN position, then ign switch is bad.

If you never loose those lights, then problem is on bulkhead or blue wire up to ballast ( including ballast itself )

note, is normal those lights dimming while cranking since ballast is retro feeding the cluster on cranking moment, not ign switch

With a Charger born in Chrysler assembly plant in Valencia, Venezuela