I recently had this issue with the retractable TV in our Aria. I was able to remove a window screen, open the window and with the TV up reach in from a ladder outside to reattach the HDMI cable. It had been taped to the back of the TV at the factory, but the tape had dried out and come off. I used zip ties to more permanently keep it plugged in.
Vicki and Mike, Aria 3901- The Wined Up Bus