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      10-25-2018, 01:23 PM   #5
xbobsix1
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Drives: BMW 440I F36
Join Date: Jul 2018
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Question

Quote:
Originally Posted by Mashman View Post
You do not want to power the camera from the reverse light signal, but you can control a relay with it. The problem is that voltage on the reverse signal drops when the car is running. You might get 12v with the engine off, the ignition on, and the car in reverse, but when you turn the engine on, the voltage drops to around 9v. When people try to power reverse camera's directly from the reverse signal they often see the camera working fine with the engine not running, but once the engine is on, the camera does not work correctly.


What you can do is power a simple relay off the reverse signal. I don't know if you are familiar with relays, so I will describe how a simple relay works.


Below is a good diagram of how a relay works. What a relay does is it allows for a small current to be used to throw a switch for a larger current. Positions 85 and 86 are for the small current, such as the reverse light signal. When there is power on that current, a coil is energized and forms an electromagnet. Position 30 is connected to constant power, such as the battery (or you can use anything that will have power when you want, such as the amplifier), and position 87 is connected to what you want to have switched power - ie the camera. When the coil does not have power, and spring will keep 30/87 circuit open, when the coil is energized the electromagnet overcomes the spring, and the 30/87 circuit is closed, and power is available on position 87 - the camera.


Many backup camera's have a relay internally, that is why they have three wires, one for power, one for ground, and a separate control wire. Often the radio is only putting out a low voltage control signal, this is not enough to power the camera, and that may be your issue. It's hard to say without knowing what wires you have for your camera, and where they are connected.





Hello,

Thank you alot for that, i realise that it does in fact have a control wire, ground and power wire. The control and ground wire are in the trunk, and that is what i know i have to connect to the reverse light, i just dont know which wire goes where.



I know its an awful image, but you get the idea. I have 4 wires that goes to my tail light. and 2 wires from the camera that should get to those wires. I just dont know which one goes where. I looked it up everywhere, but everyone seems to have different wiring for the lights than i do.


For this part, the image below is a good reference.
For another case. The wire that i have taken all the way through the panels of the car, and to the end, has an input ending, that i just plugged into a random slot where it fit, but there are 4 yellow color matching plugs it could also go into.
And also a small red wire is comming out from it, which i believe has to go to some power outlet? i just honestly dont know what wire is a power outlet in my case.


P.S. i use Posi Taps, so that is what is on the wire.

Thank you so much in advance, i really hope you can help me getting this fixed!
Appreciate 0