Reverse camera trigger wire

[jemselectrical]

Hi guys, I've installed a dashcam/reverse camera system which has a red 12v+ trigger wire that's meant to be tapped off the + of the reverse light. Sounds straightforward, but given the bat s**t crazy electrical system on the B9, I'm expecting that if I do this connection that the BSI will likely throw a wobbler, or will it be ok?

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[shtu]

I would expect that to be OK - the BSI is likely to be picky about the resistance of the circuit, I cant see a (very) low current trigger signal also being taken causing a problem.

But hey - French. I'd test it before installing the camera wiring - probe the bulb holder with a paperclip or something.

If you find it's causing problems, you could try putting a small diode in the camera's trigger wire to prevent any voltage being fed from the camera into the reverse light circuit. A 1N4001 or similar would do.


There is a connector on the gearbox - that might be a simple reverse light switch, you can meter that out and see. Might work as an alternative?

[Sol]

The official documentation (and massive red warning sticker on the rear lighting harnesses) says no more than 10ma to be drawn or the BSI outputs will be damaged, as none of the lights are powered directly but are all from digital I/O outputs in the BSI controller board.

Probably just cautionary but they seem to make a big thing of it. Expose the rear light harness and you will see the big warning tag, I ran mine off the rear 12v accessory outlet, so the camera is on all the time with the ignition, no problems there, but you can probably put it on directly if it draws very little current.

Of course the reversing lamps at 21W draw 1.75A at 12V so there is capacity there, so I'm certain it won't break it but acting weird may be the outcome.

All PSA vehicles electrical systems are run by a computer controlled multiplexer, nothing is wired direct like in 80s cars. Guess where the reverse switch goes.. it's an input to the multiplexer (BSI) - so there is no simple reverse switch.

You have the schematics James, on ServiceBox, have a look, I doubt a camera would draw enough to worry it, but here's my own take on it: I wired my front monitor into the interior lighting circuit 12v supply, as its a mirror monitor, and my interior lights then do not go off, ever, when the ignition is on and the BSI is awake, so I had to remove the bulbs completely to use the monitor. My feeling is although you won't damage it with a camera on the reverse light, the BSI will likely put the reversing lamps on permanently with the ignition when it spots the extra device, like it does with my camera monitor.

That's why I tell folk not to do it, but it's their choice. Interested to know what yours does.

My LED 3rd rear brake light too has the camera built in, and when I hooked it up initially (as per the normal brake light) with the camera, my brake lights flashed on and off repeatedly, every few seconds. I had to separate the camera feed cable ground from the brake light ground or I couldn't drive the van any more.

[jemselectrical]

The official documentation (and massive red warning sticker on the rear lighting harnesses) says no more than 10ma to be drawn or the BSI outputs will be damaged, as none of the lights are powered directly but are all from digital I/O outputs in the BSI controller board.

Probably just cautionary but they seem to make a big thing of it. Expose the rear light harness and you will see the big warning tag, I ran mine off the rear 12v accessory outlet, so the camera is on all the time with the ignition, no problems there, but you can probably put it on directly if it draws very little current.

Of course the reversing lamps at 21W draw 1.75A at 12V so there is capacity there, so I'm certain it won't break it but acting weird may be the outcome.

All PSA vehicles electrical systems are run by a computer controlled multiplexer, nothing is wired direct like in 80s cars. Guess where the reverse switch goes.. it's an input to the multiplexer (BSI) - so there is no simple reverse switch.

You have the schematics James, on ServiceBox, have a look, I doubt a camera would draw enough to worry it, but here's my own take on it: I wired my front monitor into the interior lighting circuit 12v supply, as its a mirror monitor, and my interior lights then do not go off, ever, when the ignition is on and the BSI is awake, so I had to remove the bulbs completely to use the monitor. My feeling is although you won't damage it with a camera on the reverse light, the BSI will likely put the reversing lamps on permanently with the ignition when it spots the extra device, like it does with my camera monitor.

That's why I tell folk not to do it, but it's their choice. Interested to know what yours does.

My LED 3rd rear brake light too has the camera built in, and when I hooked it up initially (as per the normal brake light) with the camera, my brake lights flashed on and off repeatedly, every few seconds. I had to separate the camera feed cable ground from the brake light ground or I couldn't drive the van any more.

Thanks for the feedback guys I'll power the camera off the rear 12v outlet supply as at least it'll go off when the ignition is off.

I've got the main mirror display supply coming direct off the battery via a fuse box so it doesn't get involved with the BSI

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[Sol]

Perfect mate, worth a try to get it working and then if you like the operation that way, you can leave it. I already like mine being on all the time, with the ignition and it is never an issue. You can also split that supply out into a mini 6 or 8-way automotive fuse box off Amazon and use the feeds for other stuff in the back like an inverter to charge DeWalt batteries as you drive...