What signal causes the hu to switch to the backup camera

[tmiller101]

VW Jetta with a 4.4.4 Joying quad HU

My backup camera functions as it should. However, I want to install a toggle switch that will allow me to turn the camera at will, but I can't figure out what turns the video on.

I have the backup camera connected to the parking lights ( I have daylight running lights) so the camera is constantly on. I checked the orange backup wire and could not find any signals on it.

Is there a way to cheat the system if I'm using a CANBus decoder?
And What are the 6" red wires on yellow RCA cable for?

Thanks,

 

[DWilks]

@tmiller101 ..Here's what I did for Manual Control of the Backup Camera. You can turn on the backup camera anytime you like, even while the unit is booting up. I also use it to view traffic to the sides rearward while on multi-lane roads. It only has power when you activate the switch. Bought cheap switches off Amazon here:
http://www.amazon.com/dp/B00HG7F37A/ref=pe_1098610_137716200_cm_rv_eml_rv0_dp
Well, it won't let me load my schematic....only list URL image to choose.
__I__ (push on/push off switch)
Cam (+)----------------o o------------------(+12V) that supplies +12V to the Head Unit)
Cam (+) ^^^^(same Connection)----------------------<>( "Back") Orange wire of Head Unit
Cam (-)---to Chassis or can go to the same wire that supplies Batt (-) Black wire to the Head Unit
In words, what you are doing is supplying the Camera (+) 12 volts that's always connected to the
Head Unit but only when you toggle the switch. The (-) or chassis is always connected to the Head Unit and also to the Camera. So, the answer to your question is the Orange "Back" wire! Hope you can follow my attempt at drawing with just a keyboard-. I had already installed a rear camera, so I had already run the power wire for the camera to the front dash. If done like mine, you will need to also run the power wire all the way from the rear to the Head Unit so that it only gets power when manually turned on. I mounted my switch below the Head Unit in the dash.

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---------- Post added at 05:19 PM ---------- Previous post was at 05:10 PM ----------

that --I-- symbol should be over the two o o symbols to show a switch

 

[tmiller101]

The other day I was measuring the voltage level on the orange wire and when I put the car in reverse nothing changed. As you say, I too thought I should see 12v there. But I saw nothing, that got me thinking and thus the reason for this question.

So, for the sake of clarification, You're saying, if I splice into the Orange wire coming out of the HU and apply 12v, the radio will think I'm in reverse and switch over to camera mode?

 

[DWilks]

@tmiller101, you are looking at it backwards-....The Orange wire "Back" is an INPUT to the headunit, not an output! It gets an input voltage from the cars brake circuit to make the headunit apply the camera's video to the headunits LCD. So, anytime that you want to power up the camera and see it's video, just apply +12Volts to the Orange "Brake" wire. No matter what's currently on the LCD, the camera's video will then be displayed. Wire it the way I did and the camera will only get power when you activate the video with the switch.

 

[tmiller101]

Thanks, Yes I figured it to be an input. I just wanted to make sure the signal was 12v and not a ground. I read elsewhere that a ground is applied to activate the hu. But obviously you have verified that not to be the case.

Thanks again,

 

[tmiller101]

http://dl-1.va.us.xda-developers.com/3/5/4/6/2/2/4/Camera_Wiring.png?key=xMNHG8lrfJsOzeq_hn_Daw&ts=1447809325[/url] Wiring DIagram