hmmm sound strange  - while i dont explicitly know the ciruit for the dash
lights the way the variable birghtne usually works is with a variable
resistor in series with the dash lights - the thing that is puzzling is
that the lights should be able to take the maximum voltage your battery
or an alternator puts out without burning anything .....

check all those fuses again with a VOM !

sorry , cant think of much else ....