Don't know your vehicle details - it helps to include them at the bottom of each post.
Mine has a thumbwheel to the right of the headlamp switch to control instrument panel illumination.
Are your headlamps on all of the time? If so, daylight levels control only the instrument illumination automatically by switching to night mode as and when.
2015 2.2 CDTi SENav 163ps manual 4x4 in Carbon Flash with 19\" alloy spare towing a Bailey Unicorn III Madrid @ 1500kg.