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Rear backup camera installation glitch

Matt2025

New Member
I just joined this forum because I thought I might get some good ideas on my installation. Per recommended installation instructions (youtube), to get 12v to the camera, the positive and negative wires were soldered to the pos and neg at the backup light at the tail light. This activates the camera only when shifted into reverse. The issue I am having is that while backing up, if I press the brake pedal the video screen goes blank for an instant. So when 12v goes to the brake light it is causing some kind of interference for and instant. It is irritating more than anything else, especially when hitting the brakes multiple times.

Any thoughts on a solution to stop this?

Regards, Matt
 

Diver300

Well-Known Member
Most Helpful Member
I suggest that you connect the camera negative to the car body, not to the light cluster, and see how that goes.

You haven't said what car it is, but most cars have light clusters where the whole cluster shares a single ground wire. Brake lights, whether incandescent or LED, will often take brief surge of current when they turn on, and that current will go through the ground wire. The ground wire will have some resistance, and so the negative voltage at the cluster will be a bit above ground. When the surge of current happens, the negative voltage on the cluster will be a bit more above ground, leaving less voltage for the backup camera, and that could be enough to make it turn off.

Having a separate ground connection to the backup camera will avoid that problem.

If that doesn't work, it could be that the car turns off the backup light briefly when the brake comes on. If so, I suggest fitting a diode and capacitor, like this:-

backupcamera.PNG
The diode should be a 1N4002 (or 1N4003, 1N4004 etc) and the capacitor should be 10,000 μF or more, rated at 25 V or more.

A capacitor like that is quite large, like the size of a C-cell battery so will need mounting somewhere. The diode is much smaller. Both components need to be fitted the right way round. The capacitor will be marked with a white stripe on the side where the negative wire is. The diode will have a band showing the cathode (labelled K on the diagram - I don't know why diode cathodes are labelled K, but they are).

When in reverse, the capacitor will charge through the diode, and run the camera. When the voltage to the backup light stops, the capacitor will run the camera for a short time, and the diode will stop current going back to the backup-light. The capacitor will only be large enough to run the camera for a few tens of milliseconds, but I think that is all you need.

I don't know if that will work, as I don't know the exact cause of the camera cutting out, or how much current the camera takes, or how low the voltage has to go before the camera cuts out, but it's probably worth a try.
 

Matt2025

New Member
Thanks for the reply. Changing the ground is an easy procedure but I don't know about the capacitor and diode. I'll try the ground change and see what happens. It's a 2004 F150 by the way.....
 

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