A word of caution. You need to remove and refit the needles to remove the plasma dials. This is fraught with danger! When I fitted mine I had to buy a second dial cluster to replace a broken spindle on the speedo.
Also the standard speedo is pretty inaccurate especially with 16" wheels fitted. (On the over generous side)
The standard dials are pretty naff in my opinion...
Do you have plasma dials fitted to the instrument cluster?
From the tiny section I can see in your first photo, it looks like you have. White dials with blue and red figures?
If you do, the switch and rheostat are likely to switch on and adjust the illumination.