Accessing Rear-View Camera Wiring Harness for Troubleshooting or Camera Replacement

My 2011 Agile came with an Eclipse GPS Navigation and Audio System; it is also equipped with a rear-view camera. RT has installed a generic camera in lieu of the more expensive Eclipse brand camera. I have read somewhere that the original Eclipse camera is powered by the head unit at 5-volts. In order for a 12-volt aftermarket rear-view camera to work, RT used an adapter and spliced a 12-volt power from the Sprinter reverse lights. One drawback of using an aftermarket rear-view camera is that you loss the manual "always on" camera feature of the unit.

Recently, my rear-view camera intermittently stops working at night, especially when it gets cold. The camera would start working again when it gets warmer during the day. I thought there must be some loose wiring connections to the camera that possibly exacerbated by moisture or condensation build up. I pulled out the head unit and replaced the loose push-in Coax-to-RCA connector for the camera with a better compression type, but that did not solve the problem. I called RT on how to access the rear-view camera wiring harness and was told to remove some panels just after where the camera is mounted, but Agile has a rear overhead cabinet on that area and that would be a pain to remove.