I looked a little bit in this forum area and did not see any mention. I am sorry if it has already been asked, BUT
I have an RV with 3 cameras that look towards the back of the vehicle 2 on the mirrors and one in the back. The RV used to have a B/W tv for the cameras. We removed it and installed an Eclipse double din/nav unit. We kept the B/W tv in the dash as a switcher. The cameras have s-video calbes going into the back of the tv, then there is a rca video output that we used to go to the Eclipse. The video coming out of the back of the tv is a reverse image. The cameras are sending a reverse image to the driver's dash (the TV). So in effect the Eclipse unit is getting a reverse image (left-right). We want to reverse that final image. On the back of the tv is a switch that says: Norm-Rev That switch only effects the image on the front of the tv. It does not change the rca video out. Is there a company that makes a 12 volt image reverse inline on rca video? The Eclipse unit does not reverse in it's menu. I contacted a tech about that already. Thanks.
From your post I see that you have decided to upgrade to the very nice Eclipse unit...a wise choice. Since nobody likes b/w anymore, I would suggest eliminating that portion. It seems you only kept the tv to use as a switch for 3 s-video inputs, but now get the reverse image causing your problem. I don't know of an inline image reverse for 12 volt application, but I did find a 4-input to 1 output switch that seems to fit your application perfectly. This particular unit has 4 inputs for either s-video or composite video (the yellow plug) and 1 output for either s-video or composite video. With this unit you could just eliminate your old school b/w tv as a switch and put the 3 s-video inputs in with 1 composite out to your Eclipse unit. This would hopefully eliminate your problem of using the tv as the switch since it appears that may be the cause of your image reverse problem.
https://www.svideo.com/svideo4to1.html
This is just 1 brand I found and appears to be about the size of a brick so it should be much easier to conceal. I'm sure there are more brands on the market if this unit does not work for you. If this does not correct the problem you may need to look into replacing the cameras since many of the modern backup cameras likely have the reverse image built-in and older cameras may have relied on the monitor to reverse the image.
Hmm, just in case anyone finds this thread and is wondering if there are any modules out there which will reverse an image(from normal to mirror, or vice-versa), I found one out there from Crimestopper, product number SV-NIM
Here's someone who stocks it:
https://infiniteelectronix.com/crimestoppersv-nimnormalimagemodule.aspx