Backlights won't work / please help

Hi,
I have a '93 Sabel SW and since a couple of days the backlights won't work. I checked all fuses and bulbs - everything is ok. Return lights, brake lights and indicators are fine. What can this be and how can I fix it???

Are you getting power to the light sockets? If yes, check the grounds, and the sockets themselves for corrosion. If no, check the switch. How did you check the fuses and bulbs?

Checked everything and found out that switch was broken. Thanks very much for your help.