Interior lamp defeat switch
 

I see this switch mentioned in the shop manual in the wiring diagrams. The owners manual does't talk about it at all. I notice the knob on the light switch has a click when rotated all the way to the right or the left. Is the click that is all the way to the right this light defeat switch?
My dome lights haven't worked and I'm delving into my parasitic draw that I have going on. All the wires on the headlight switch that I could see looked fine. Pulled the switch and found 2 wires on the backside that the rats had got to. Trip to pick and pull tomorrow is in order. I also found when I remove the time delay relay that my draw goes away. I'm going to see if the wires fix things and if not I will get a new delay timer. The wires ought to at least get the dome lights working.

Yes it is. It is also the dash rotary dimmer switch.

I knew about the rotary dimmer switch from previous older vehicles. Never came across this light defeat switch. Thanks for the confirmation.
Made it to pick and pull today and got the pigtail I needed along with a time delay relay. I now have my dome light working and the buzzer works if I open the door with the lights on. Good progress. I also replaced the time delay relay and there is no draw now. Time and a few drives will be needed to see if it is really fixed as it has been taking a drive to get it to come back. We will see. Overall pretty pleased with the progress.

Just came in from putting everything back in the dash. Drivers door does not activate the dome light, but does the buzzer for the key in and headlight on. The other doors activate the dome light as they should. Something is still not quite right, but if that is the extent of it right now. i may I've with it and see how things are after a drive.

Gotta be a bad wire on that switch. So far as I know, key buzzer, and everything else uses the same switch.

It seems strange it works for some things and doesn't for another. To me it has to be beyond the switch.

I think the switch just provides a ground path...... Might be able to find wiring diagrams for your Van here. Yes, it's a Russian site, but, I have been using it for a couple years, with no trouble.

I have the factory manual.It's just finding the right diagram and understanding where the issue might be.

Hhhmmm... Using my usual go-to site for wiring diagrams..... It appears there is only ONE wire going to the front door jamb switches, and it only turns on a single courtesy lamp. Which just can't be quite right...... How many wires do you actually have going to your door jamb switches?

I haven't taken the panel off to see. I keep meaning to get out my manual and see if I can determine that. Right now I'm just relieved that I've made this much progress and don't have any electrons being sucked somewhere.