Hi Have two FH’s with the same problem. The main interior lights dont work from either the switch on the night heater panel on the back of the cab, or the dash mounted switch. Its not a fuse, bulb or a relay there ok. Every other light in the cab works fine. Its just the two main interior lights mounted in the roof. Anyone else had this problem, any help appreciated. 
I had something like this once, check both the red lights on the drivers and passengers door, believe it or not they are actually switches as well as lights - I remember something daft like this happening and think this was the reason.
stagedriver:
I had something like this once, check both the red lights on the drivers and passengers door, believe it or not they are actually switches as well as lights - I remember something daft like this happening and think this was the reason.
Thanks will have a look, not sure it will rectify the issue though. 
There’s not a switch hiding to the left behind the steering wheel, down diagnoly from the handbrake is there? It aint visable until you look round the wheel but that’s where I found it once. Couldn’t understand why the door and main night (red) lights are a separate switch…
HERE…
