dash lights could be supply, control and or ground....supply, see if you have 12 volts out of the headlight switch at the rheostat part of the switch...(the resistor that controls brilliance) if voltage is there and its output is changed in varied voltage by turning the rheostat...then check supply to the instrument lights....this is usually an orange wire.....if the voltage is going to the lamps via the orange wire and the bulb holders...then you may have a grounding issue with the cluster itself not going back to ground through the body. Easy checks again with the VOM both voltage and grounding paths.
