I'm betting Ford has made is so you can't hook up another camera unless you buy it from them. I asked about getting a different one from ford and they told me they only make the one for the tailgate. Call this company and ask maybe they make an accessory to hook the ford monitor up to a different brand camera.
I have used these camera's on our farm equipment for about 8 years now and they hold up real well. They are wired. The company does offer them in wireless but the John Deere mechanics said they have mounted the wireless models they said the picture gets fuzzy with bouncing, and diesel engine noise. So since I couldn't return the wireless model I have stuck with with wired model.
Cabcam; home -
http://thecabcam.com/index.htmlYou can get a kit 7" monitor, 65' cable, color camera with night vision. Hook into cigarette lighter. About $250 from John Deere
http://thecabcam.com/cc7m1c.htmlThis winter I ordered this camera that attaches to license plate. $109
night vision lights too.
http://thecabcam.com/lpc634.htmlWith a 3.5" color monitor $110
http://thecabcam.com/cc35dts.htmlthe 3.5" monitor - Does not have a window mounting suction cup. I went to ebay ordered a window mounting bracket for my garmain GPS. I epoxyed the monitor to the garmin braket.
http://www.ebay.com/itm/Suction-Cup-Mount-and-Bracket-Clip-Cradle-for-Garmin-Nuvi-50LM-GPS-Receiver-Part-/161160852660?pt=LH_DefaultDomain_0&hash=item2585ef74b4Good Luck
