Instrument panel dimmer knob removal
The knob actually has a lid cap on the front (the area where they screened the graphic icon). They did too good a job there, so you can't really see the gap -- unlike on the dash, panels, etc.
With a lot of luck, and a really tiny flat head screw driver (jewellery type) or scalpel blade, you might be able to open the lid without damaging the knob.
There's a nut holding it inside. You could tighten it up once you have the cap opened. To get the lid out is the tricky part.