What is the point behind such a function?
I have noticed a slight difference only
between the two positions on this rather
odd dash mounted switch...

thanks

 

Its a test All it does is make the dash clock dim for night time and bright for daytime. It doesnt affect any other instrument in the car at all

Most useful.

 

..apart from altering the brightness on my alpine head unit...

if you have a head unit that can "dim" when the sidelights are switched on, then this switch is a good place to take a feed from since you can then also manually override it.

 

Excellant idea Lee.
Now why didn't I think of that.