Has anyone seen this concern before? Please see Youtube links below.

Before I go poking and prodding in near 50 year old wire, I thought I'd ask if anyone has seen this concern before.

Note:
All EXTERIOR electrical lighting works properly under ALL conditions.

Dimmer switch only allows full I/P backlighting or no I/P backlighting. Also the dome light feature is inoperative. The switch has operated this way for years. The concern in the videos is new.

Suspecting:
Faulty electrical switch
Poor ground
Shorted wiring/connector/component/Instrument Panel

https://youtu.be/CO2scHN8d5o

https://youtu.be/N0XcM3lz-FM