Don't miss out on looking at lots of links here, for tons of info, one might not expect: https://www.winnebago.com/owners/owner-resources The links at the top right are an opening to a vast amount of info -IF we can sort it!
Bottom of the page has some contact info which can bail us out at times.
For turing on the light, there seems to be lots of different versions of different RV, so I'll thro these in as well.
Some have a "soft spot" on the back of the lighting head to press. Some roll the dash light adjustment all the way to click.
But there may also be times when if you know where an item is located, finding it on the parts drawings can lead to a breakthrough on what and how.
This is for your RV:
Actually, I think you mean turn the dash backlight dimmer switch, that is next to the headlight selector switch. Turn it all the way toward the brightest dash light setting and it should click when turned past a detent.
This is the same as turning on a dome light in a car.
On some RVs this is the only switch to turn on the Map/reading light on the driver’s side. On others that dash switch powers the light but there is another small switch on the light itself.
I have the latter style and I keep the dash switch on all the time and use the switch on the light to turn that light on and off as desired.
The passenger side has a rocker switch on the dashboard closer to the passenger side that does the same thing.
I have a 2005 Adventurer 38R and had to ask one of my kids how to turn on the light. It is just like in your car, the interior light switch from the manufacturer is the key.