Wiper issue is probably due to a faulty wiper relay, a black or grey-looking cube located somewhere near the engine fuse panel. Problem should show up moreso when wiper is being used in the "intermittent" mode.

"Light out" indicator only senses exterior lamps...burned out dash bulbs are not part of the circuit. Replace where necessary. You are going to have to pull the cluster to do this, so go ahead and replace all of the dash bulbs while you are in there.

As the other posters mentioned, there is an illumination knob near the gauge cluster that controls brightness. Even at max illumination, it's not very bright anyway.

A lot of quirky electronic problems can sometimes be solved by replacing all of the aging fuses in the panel. If and when you do, make sure you get the quality ceramic fuses with the dull-plated silver leads, not the crappy plastic ones with the shiny gold leads!

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car