rear view camera troubleshooting

I have a customer car with a Pioneer avic n2 system. (37 Ford PU Hotrod.) The rear view camera is not working. Is there some way to check the camera to see if the camera itself is bad? I can access the N2 remote box but not the camera without removing the truck's fuel tank. I checked resistance on the video cable through the camera- 757 ohms. The video screen is black with the 'image reversed' statement showing. It would be simple if I had another camera to plug in and check but I don't. How can I determine if it is the camera, wiring or what?

Thanks 

Chances are the camera is the problem.  You can check a few other things to verify.  If you can get to the power wire for the camera, disconnect it from the power source. and with your meter set to the diode test function, connect the black lead to ground and the red lead to the power wire going to the camera.  Notice the reading.  Then reverse the leads, black on power and red to ground.  Notice the reading again.  One reading should have been in the area of .550   give or take 150 or so.  The other reading should have been much higher,  1.xxx.  If this is correct the power wire for the camera is still connected to the camera.   Then set your meter to ohms and check from the shield of the RCA jack to ground.  This reading should be near 0 ohms.