As you know, you can use this DVD AV Receiver with a rear view camera. And also it can be installed to switch automatically from the video to rear view image when the gear shift of the car is moved to Reverse position.
But it is important to use a camera which outputs mirror reversed images.
Otherwise the screen image may appear reversed. And this means that you will see the rear view reversed in the monitor. And that may cause accicent and injury.
To solve this problem, first check your rear camera whether it has the capability to output mirror reversed images.
If it is, then check the wire connections of the rear camera using the operation manual or ask a technician.
Also check the settings of camera polarity if it is set properly or not in the system menu when connecting the rear view camera.
You can download the operation manual (pdf file) by clicking here
I hope this helps.
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All the best.