Hello,

The only thing I can think of is the dimmer function - to make the display less bright at night?  I hope this is what you are trying to find out?

To turn the dimmer on and off:

Press and hold the 'select' button (the setup display appears).

Then repeatedly press the 'select' button until "DIM" (dimmer) appears.

Turn the control knob to turn the dimmer on or off.

Press and hold the 'select' button again to confirm the setting for the dimmer and exit setup.

Hope this helps?

No problem - glad it helped!