My dash on my 1994 XJS convertible is out to replace heat and A/C housing and blower motors. While it is out, the directional and high beam dash lights across the top of the dash are extremely dim. Should I just replace the bulbs or is there another fix?

 

You can try using much brighter LEDs for these items.

 

I bet the inside of the binnacle is coated with dust and soot.
Clean with mild solvent, EtOh or just a damp cloth.
Don't scrub it, just wipe.