Video on VMS645

I have the VMS645 and Video 1 is hooked up to my rear camera. All works fine and full screen video appears when I go in reverse. I do not have Video 2,3 or 4 hooked to anything.
I want to use video 2,3 or 4 to display my GPS screen. Is this possible? Ideally, I would be able to push "Video" button at any time while driving and see either Rear Camera or GPS (or any other video input I might use) in full screen.
The obvious reason for wanting this is that the VMS645 screen is much larger than any GPS screen.
*Note: The setup screens do not even list a Video 4 option.
Greatly appreciate any help and hope this setup is possible.

re: video on ports 2~4

Hello Bob

To use the other video, just plug in a composite video source. As you look at the back, the most-inboard BNC socket is port-1. 4 is then the outboard.
As the socket is a BNC-type, you'll need a little mechanical adapter to whatever your plug is; usually an RCA type. Does your GPS have something like this?



Thanks Art. I left the backup camera on #1 so it works when shifted in reverse. I just set "Default Video" to the new connection that I am adding.


Glad this worked out smoothly