I'm not sure about the hazard switch, but the rear window defrost switch has an internal contact for the light - sometimes is corroded. Mostly I see this in the seat heater switches where drinks get spilled, but that contact delivers the switched +12 to the lamp; the wire to the lamp socket is the ground. Make sure the sockets are pushed into the switch with the contact in the correct orientation (if its possible to not) and my experience with those lamps is you can look at them sideways and break the filaments. Probably because I'm too cheap to buy lamps made this century.

The dash is very dim. You could short the dimmer switch (bypass it) for I think you will never, never find yourself needing to DIM the dash lights. Yes, they can be faulty, but I haven't found that to be the case if they work at all. Every year I age those lamps get dimmer.
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Art Benstein near Baltimore