Rear view camera

Just had an experience with a wireless rear-view/backup camera and 7 inch monitor that I got off of EBay. Hard wired the monitor into my dash 12 volts and the camera into the running lights. So to have the camera working I have to have the running lights on. No problem there as I normally run with the lights on anyway.I got the wireless system from China pretty quick and all was well. Tested it on my bench with known reliable 12 volts and it worked great. Picture was clear and it had many of the features are more expensive system had like a range finder to tell you how close you were to something when backing etc. All in all I paid less than $80.00 including shipping form China. After testing for a couple of days I put it into the motorhome and it ran as it should for ONE day. The second day I went to the motorhome to show the wife my handiwork and it would not make contact. Got message no signal on the monitor. Got on the ladder, took the camera down and moved it right next to the monitor and still no signal Now is it the camera or the monitor receiver that is out? I have no idea. I put both on a known 12 volt supply and nothing happened but the monitor was alive and seemed to respond to the menus it has via buttons on the monitor. By the way there is a wire you can wire into the backup contacts on your rig so you can have it come on automatically when you backup but I just wired it so that it comes on anytime I push the power on button on the monitor. That is a supported option they provide. Anyway I contacted the Ebay seller and they responded in a day and told me that they would gladly replace the camera but I would have to send it to China at my expense and gave me a restocking number. They also gave me the option to buy a new camera and a reduced price of $20.00. I took that option and am currently waiting for it to come again from China. Knowing these kind of things when dealing with off shore companies I was not surprised. But if I had gotten it form a US company the replacement would probably been a lot easier and quicker. Like I said before, on the bench it did everything I wanted the system to do, and I will have to see what the end results of this gamble will be. But I was willing to take the chance at the great cost difference between this one and others I have seen. I have a perfectly good wife to back me up anyway so if it does not work, no big deal to me as it was kind of an experiment anyway.