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Discussion Starter #1
Hi all!
So, I installed a reverse cam which goes into the license plate light. Since I have the regular radio, I installed a rear-view mirror-screen.
I connected both the cam and the screen to the reverse light + and - in the trunk.
My problem is that when reversing, if I turn the steering wheel fast, or when I keep the wheel all the way to the left or right, the video in the screen dissapears.
I found out it is because the voltage in the reverse light goes down from 12 to a little above 10 when I turn the steering wheel, and maybe it is not enough for the screen (or the cam).
The solution is to install a relay, so that the signal from the reverse light will trigger the relay and the cam and or screen will get a stable 12 volt.

My question is: is there any stable 12v source in the trunk which I can tap, or do I have to bring a 12v source from the front of the car (maybe from the fuse box on the driver side)?
Or maybe I can get the same reverse light signal from near the driver's fuse box? I read there should be something like this in the kick panel on the driver or passenger side, is that correct? How do I know which cable is it? there are quite a few....

Thank you!
 

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I would check why the voltage drops like this when you move the steering wheel. Doesn't make sense to me.
Check the resistance on the wire you are using. Perhaps connect to ground on the front or chassis rather than using a back to front going wire for ground.

You can also look for a different camera that can work with lower voltage. I installed a camera and it works fine even with 6v.
 

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Discussion Starter #3
I think my problem is not that the camera doesn't work, but the screen. I think the screen is turning off when the voltage drops.
The screen (a rear-view mirror with an embedded screen) is in the front and it gets the video signal and the +12v and ground from the trunk, form the reverse light.
The drop in voltage I measured in the trunk.
 

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Maybe the wires are not that good (bad conductivity). Did they come with the kit or did you choose them yourself?

Measure voltage near the screen and see how low it is.

As I said, try to connect ground of the screen to a ground point in the front (try cigar charger first) rather than going to the rear and back. That should reduce resistance and make the voltage drop smaller. It might create other issues (noise in the video) but at least you will know if that is the issue.
 

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BTW, I think that the voltage dropping like that when you turn the steering wheel is a problem. Perhaps the battery needs replacement. How old is the battery?
Or it can be the alternator.
 

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Discussion Starter #6
BTW, I think that the voltage dropping like that when you turn the steering wheel is a problem. Perhaps the battery needs replacement. How old is the battery?
Or it can be the alternator.
The battery is new - less than half a year
I have no other apparent problems.... how can I check if the alternator is ok>
 

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Discussion Starter #7
Ok... it was a grounding problem
I didn't connect the ground (black cable) from the screen because I read somewhere that the screen gets the ground from the video camera so there is no need for dedicated ground.
So I tried to connect the ground from the screen to a real ground and now it works as it should

Thank you! (you didn't tell me to do that but you mentioned the grounding and that made me think that was the problem)
 
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