This may be a tough one for several reasons?
One is that Winnebago gives us good support online for the things they build but NOT much on the things they buy from others and install. That includes the generator where we get info up to the point where the Winnebago wiring meets the generator wiring.
This will be on the 12Volt DC here:
https://www.winnebago.com/Files/File...ram/Wiring.htm
On sheet 1 ,where 1 and C would cross, we find a drawing of the plug where the Winn meet the generator wiring. The colors don't match what I see, so this may not be the correct plug, wires may have been changed or info not totally correct?
In your picture, I don't see a wire loose but it looks more like they chewed through and left gaps in several wires, all small gauge, white?
That brings the question if this is the same plug but different colors or a different plug?
I'm guessing this IS NOT the correct plug as shown but it might be possible to sort by checking continuity from here back to the Winnebago plug if you are able to spot another set of plugs?
Click this snip to get a better view or go direct to the drawing for the big picture?
But IF this is the correct plug where Winn meet genset wiring, there should be ID labels on the smaller wires!
Example!
If you are able to find the wire ID by digging back further on the wires, then you can find which goes where using this "decoder" chart:
https://www.winnebago.com/Files/File...ical_guide.pdf
This may be where we have to go to the generator builders for info on their wiring!
But it should not be the cause of the lights, etc. in the RV not working!
Their should be 12VDC coach batteries that would power the inside RV things like lights, vents and water pump, so pretty much a separate question to sort.
Same batteries for cranking the generator but not the same wiring in most cases.
Looking at the second question, if the lights work when the RV is plugged in, that says power is getting from the post to the cord and all the way to the converter which makes the 12VDC to charge the batteries and run those items. Breakers, converter, etc. are all okay.
But if it all stops working when you unplug, it really says there is a problem with the batteries not being good enough to charge and store that charge OR
The wiring from those batteries is corroded or bad.
My first guess would be the batteries are bad unless you know different?
One way to check is test the voltage on the post at the batteries. That should be near 12.7 for a fully charged good set of batteries.
Then when you plug in and the converter starts working the voltage may jump up to about 13 in many cases as the converter tries to recharge them.
Idea is that you want to see the charge is getting to the batteries and they are expected to hold that charge for hours as you use that charge.
If the charge is getting to the batteries why is it not there for use after shutting down the converter?
Bad batteries won't hold a change, or bad wiring from the batteries to where it is needed?
Do a bit of checking and we can go more into how the power gets from batteries to other things to use it but I'm leaning toward bad batteries or connections right there?