The reversing camera on my 2014 Tribute has stopped working and would like to try and fix it rather than take it back to the dealer under warranty.When I put the van into reverse the monitor which clips onto the rear view mirror lights up but just gives the message No signal.I have checked the connection from the camera to the extension cable and this is ok.I assume there must be some sort of control box hidden somewhere but I can't think where?Hopefully somewhere accessible .Any suggestions greatly appreciated.