Courtesy Light staying on/ Dash lights not working

So I've pulled the dash, disconnected the light switch, ignition switch, so I'm thinking maybe bulkhead? This did have a complete wiring harness within the last three years. My wife reminded me it seemed to start having problems after a trailer ride. Things I've not checked include the dimmer switch. What else should I check. With all these things unhooked still get positive continuity with ohmmeter running from positive cable to anywhere on the metal of the car.

So how to test bulkhead, fuse block, (Both look fine) Have had prior issues with fuseable link but car starts and runs fine.

(again both battery cables are off the battery and not touching metal)

Love some ideas and how to. Will be going back to review the replies again and try some more items.