Do you have the dome lamp with the 3 position selector switch on it ?
- On - off - On with doors
Does the dome lamp come on when you rotate the panel dimmer all the way up ( past the indent click ) ?
Do you have a relay installed in the interior lamp relay slot in the cab fuse panel ?
did you try changing the bulb if the switch or panel dimmer don't work ?
Owners manual - Download a PDF of it :
when you say "neither does the top brake light work" is this the cargo lamp part or the CHMSL ( Center High Mount Stop Lamp ) ?