Bizarre Rear Camera Issue

[lothian]

I'm t'shooting a Chinaseum-brand $30 license plate mounted rear camera. yup... one of those POS things. The thing was presented to me as functional-with-a-caveat, and just one day prior everything was working as expected.

 

The Problem:
The Kenwood headunit automatically displays rear camera video when the car is shifted into reverse only when the trunk lid is open. When the trunk lid is closed, the headunit display goes black; iow, rear camera video cuts in and out when the trunk lid is moved up and down. This headunit has a "CAM" button to manually toggle display of the rear camera video when the car is in reverse, but video displays on the screen regardless of trunk lid position!

 

I discovered a broken solder splice within the black video cable at a flex point under the trunk lid. The video cable conceals three individual miniscule conductors. I delicately re-soldered each splice, wrapped each splice in heat shrink tubing (HST), wrapped the bundle in HST, then put the repair where it would never again be affected by trunk lid movement.

 

My careful repair promptly made the problem worse.

 

The New Problem:
The headunit won't automatically display rear camera video when the car is shifted into reverse regardless of trunk lid position; however, just as before I made my repair, the headunit displays rear camera video when the "CAM" button to manually toggled while the car is in reverse! I'm stumped.

 

Here's the whole shebang, all laid out prior to installation. I'm certain this is a familiar mess of wires to many viewing this post.

 

The splice I repaired was in the video cable (top image).

 

I connected the red wire from the power cable (middle image) to the red wire from the video cable (top image) to a tap connector attached to the 12v conductor for the car's reverse lamp. I connected the black wire from the power cable (middle image) to a tap connector attached to the ground conductor for the car's reverse lamp. I connected the red wire from the other end of the video cable (top image) to the wire at the headunit labeled "Reverse". This is the extent of the power wiring for this camera, and everything worked as expected prior to the issue with failed splice.

 

I have no idea how to t'shoot this problem at this point.

 

To the eyeballs of this layperson, straight 12vDC juice flows directly into the "Reverse" wire at the headunit from the car's reverse lamp conductor via the red conductor within the video cable (top image). I presume when the headunit senses 12v on this wire (when the car is shifted into reverse) it switches the display to show the camera input signal. Again... it works--iow, displays what the camera sees--when I press the "CAM" button on the headunit while the car is in reverse, but the headunit won't automatically display what the camera sees after I shift car is in reverse like it did before I made the repair.

 

I've checked--and re-checked--all conductors and splices and I have no idea how to t'shoot this problem at this point. Any one with actual experience a/o knowledge with these crappy Chinaseum rear cameras care to post suggestions on what do I need to do?

[Kyblack76]

My reverse cam on my kenwood can come on, when i go to reverse, or parked, or even driving.  Not sure what you have going on, but, i dont think just a "im in reverse" deal, triggers the source switch, as, i csn bring mine up, while going 90mph,.... forward