Side mirror camera inop - help needed to troubleshoot

My Velvac camera has a black 1/4" cable with 4 wires...2 of the 12V power and 2 for the video. Mine has aprox 3' of it inside the front cap before coupling to another cable.

You have two connectors in the side camera circuit. One is probably close to the camera itself and the other is to the back of the monitor. I have had the connector come loose at the back of the monitor before. The camera connector may also have been exposed to the elements and needs to be cleaned of corrosion.

We have a 2013 Bounder with the same issue on the left side. The cable comes in through the mirror base and side wall(maybe a foot or so), and connects to a longer cable that runs to a video-in block(not sure if that's what it's really called) mounted to the firewall. It unites the left, right and rear cameras. From there, it went to the stereo. I've since added a monitor on the dash, as looking down at the radio was inconvenient and dangerous. Anyway, I tried swapping right side for left, to test, and the extension cable/block were ok. I've since been informed that it's probably a 'bad camera', and the only option is to replace the mirror head, as it's not serviceable. I emailed Velvac and got the 'new' part number. Haven't pulled the trigger yet, as I can see just fine down the left side with the mirrors, and can spend $300+ more usefully.

On my MH there is a in-line connector to the side camera up front under the "hood". Side cameras come normally with a short lenght of cable, not enough to reach the dash.
Siggy

ohm out cable or shoot it if you have a toner. If not pull camera and run a temp new cable from it to radio via shortest length.