AC & Vent Dial Control Lighting

[atomiclord]

S3 AU, so the nice dialy-type controls and such. Ever since I bought the car the AC button light has never worked (button works fine, just not the light) and the left half of the dials often required you to turn them before the left side lights up.

Since changing the factory stereo for a single-din one I've noticed all the lights are doing this now. So to get the dials to light up you have to turn the vent, the heat and the fan speed dials until they light up.

What's the problem here? How do I resolve:
- The AC on indicator light and
- The dial lights malfunctioning

The interesting thing is that after the new deck went in the clock backlight worked again