I looked it over a bit and had a thought to try but without lots of the info we might need to get the real idea!
Am I correct in thinking this is the drawing section you are working?
Are you also aware of this list to decode the wire IDs:
https://www.winnebago.com/Files/File...ical_guide.pdf
This seems to show both TR and MD are positive battery feed to the monitor with MP being the ground. Have you been able to check all of these feeds at the monitor? My thought is that it may require all to get the proper output. Since we have no info on how the monitor powering works, it may be something like an AND gate where both input have to be positive to get a positive out?
No real idea without info on that but just random speculation! Just a point to check for something obvious to show?
__________________
Richard
Why no RV year, make and floorplan on MY signature as we suggest for others?
I currently DO NOT have one!