TV and LED on 2860DS malfunction

[Mall Man]

Hi to all you knowledgeable people. I have no electronic or electrical experience so I'm hoping some guidance is available from the august group of readers on this forum.
I have a Sunseeker 2860DS (2016) that developed a problem with the front TV and dinette LED light. A month or so ago the TV would stop working but if I fiddled with the power cord (DC cord into cigarette lighter connection in front right cabinet) it would return to service. On advice from a service person I removed the complete socket to find the back of it partially melted and the DC plug also had heat damage to the end (so much so that I could not remove the end cap without it shattering). The fuse inside the DC plug had not blown.
I ordered a new Winegard socket, making sure I labeled all the plugs and wires so I could get them back on the right fittings. After replacing everything (including the DC power cord) the TV and light still don't work.
My current park neighbor is a master electrician. After more than two hours of troubleshooting we've concluded something is still wrong. Twelve volts gets to the socket but only 2.5 volts goes to the TV. Seems only about 7 volts goes to the LED light. Our thinking is there is a short down the line somewhere but without schematics we have not idea of where to look.
We think it might even be a problem in the circuit board of the new Winegard socket. Your thoughts welcome. Thanks in advance. dj