interior lights,auto lights switch on dash

I have a 93 g20 conversion van by tiara,the dome lights won't come on when the doors open or by the headlight switch.There's a auto interior light switch on the dash,on/off,it has no power to it,any ideas.I checked the fuses,there is some empty fuse slots but don't know what there for.thx tom

Check fuse no. 1
Dome and horn and cig lighter?
Does horn or cig lighter work?
MT