Wiring in rear camera

[The Wanderer]

Hi there.

I'm trying to connect an after market rear view camera, which was already on my van, to a newly fitted Pioneer head unit.

So far I found the cable from the after market rear camera and wired up and connected the video/screen to an RCA plug to connect to the 'video in' on the head unit.

I was thinking I'd connect the red power lead to get power for the camera from the connector block under the gear shift. Would that work OK and can anyone tell me which cable there is live please? I'd also like to connect the reverse sensor cable and was wondering if that could also connect to the same connector block?

Also what would be the best way to connect? Should I try to add the bare wire(s) into the block, or cut the cable(s) so I can make a dual connection in some way?

Your thoughts appreciated, thanks.

[The Wanderer]

I figured out through looking at various posts that I could pick up wiring from the cables that would have connected to the original Mazda unit. This had clearly been done before as there were dual connectors with remnants of cable connected to the 5 way terminal block. I connected to live feed (red/green) and reverse input (red/yellow) but sadly this is still not working.

I tried checking the voltage where I had connected the live feed to the camera and this read around 11.6v. I was expecting it to be 12v and wonder if this may indicate an issue. If so what might cause it? Would the thickness of cable I've used make any difference? I only had a slightly thicker cable than the original to hand, so was wondering if that would mean a higher resistance or something. Actually wouldn't that mean less resistance?

Any thoughts please?

Thanks

[g8dhe]

It will depend on the battery voltage of course, did you check what voltage is at the battery to start ?
Then it will be via fuses and switches for the feed, what is the voltage at the feed point ?

[The Wanderer]

Hi Geoff

Thanks for your input. How do I check that please? Wiring is not an area I'm naturally good with Would I put a meter across the original multi-plug connection where I'm picking the live feed up from (with an earth to chassis)? If so I think I tried that and it was the same there.

[g8dhe]

Well start by checking the actual battery voltage on the lead terminals of the battery that is supplying the power, not the connectors, but the terminals themselves. That gives you a reference voltage, after that the voltage may fall as current is drawn thru the connectors and fuses, switches etc.
Then check the voltage at the end of the circuit furthest from the battery without the device drawing power, if the voltage is much the same when no current is being drawn then you know that you have connectivity at least, then connect the device that is drawing power, the voltage if your drawing a significant current, greater than say a few hundred mA, then you can expect a small voltage drop 0.1 or 0.2 volts say, if its any greater then suspect poor connections/corrosion/dirty switches etc enroute.

[The Wanderer]

Thanks Geoff, that's really helpful. I will give it a try. Is it likely the camera won't operate if it doesn't get the full 12v?

[g8dhe]

No they will often work down to a very low voltage! Modern cameras will be using 3.3 volts internally and will regulate the voltage down from 12 volts anyway!

[The Wanderer]

Hi Geoff

Interestingly, I checked across the battery terminals and got 12.6v but couldn't get the voltage to read at the cables I was trying to connect to the unit, so I guess there's an issue with them.

I then decided to try connecting into the reverse signal bleep cable at the box down by the acclerator pedal. I read on a thread here that it was the red/yellow cable leading into the blue box. I was unsure if it fed in from the top or the bottom as there was a red/yellow cable both sides but decided it looked like it fed from the top. I cut the cable (as I was happy to stop the bleeping anyway), tested it and was pleased to find it had 12.6v. On a whim, before cabling it up, I thougt I would check what happened when I engaged reverse and found I still got the bleeping!

This worried me rather as clearly the cable I'd cut was not the intended one and I wasn't sure what I had actually cut. I used a cable joiner to reconnect and hopefully all is well. I haven't spotted anything not working as it should yet.

Obviously I'm still keen to find a way to wire in the camera, but my confidence is waning slightly! Someone suggested to me that I wire into the cables under the gear shift but I'm not sure how to go about that. How do I know which cable is which and which one(s) to use?

To be clear, I'm trying to cable in a power feed for the camera and also the reverse signal feed to the head unit so it auto switches to the camera.

Any ideas please?

[g8dhe]

The Red/Yellow wire anywhere between the gear selector, sound warning system, reversing lights, Radio etc will go High to 12v when Reverse gear is selected, and will normally be low at 0 volts if using filament lamps in the reversing lights when not selected. Its normal to pickup the wire at the tailgate lights where the reversing light is.
Not quite sure what you ended up measuring but sounds odd!
See the diagrams for more info, the gear selector is top right of center;


The Revering signal is already sent to the radio loom and is present on the ISO A3 pin again as Red/Yellow in the loom itself, once its in the ISO loom then colours aren't defined reliably. Its pin 3C in the Mazda loom connector for the radio.


What year is your vehicle, the diagrams are only dated to 1999, but loom colours normally stay the same no matter what year.

Ah just noticed the missing images are back again click the little broken image icons for the link to the diagrams, there is something amiss with the forumn software at the moment with external image links.

[The Wanderer]

Thanks Geoff. I looked at the wiring diagrams previously but couldn't make sense of them. I'll give it another go.

It's a 2002 V6, hopefully same wiring as you mentioned.

[The Wanderer]

Hi Geoff

It seems the red/yellow convention doesn't apply throughout with my van, which is a 2002 V6. None of the connectors at the gear shift have this colour coding!

I picked up a 12v live red/yellow feed from the original loom to the stereo and still couldn't get the camera to work.

I'm a little suspicious that the cable I found which I believe to be from the camera doesn't have a neutral wire. Searching online for the camera (an Eclipse), all the cable diagrams I found had 4 wires, one of which was a neutral.

The only other thought I had was whether the RCA plug has to be specifically for video, or if it's just a standard RCA/Phono coax.

Anyhow, at this point I've had enough and I think I will just order a new camera I know should work with my Pioneer head unit. Obviously that will involve the fun of feeding the cable through the van but at least I know it should work! I may check the connections to make sure first though!

[g8dhe]

No RCA/Phone plugs are standard for whatever purpose, the -ve/earth wire is often the shield of the screened wire carrying the video. It could be that they have varied the colours in the 2002 versions.

[The Wanderer]

Thanks Geoff

To be clear, the cable I found had only 3 wires rather than 4, which theones I found online had.

[Greenmachine96]

Hi

I'm jumping on this as there seems to be the right level of knowledge kicking around.

I have a camera mounted into the spoiler itself, and I've found the severed end of the black wire (containing red, black, yellow and white and what appears to be shield (bare wire) behind the driver's seat.

I want to (as simply as possible) check it works and then connect it up. I'm hoping I can run a cable straight to the back of a head unit and get all the necessary power/earth from that? I see the loom does have a reverse sensor, which presumably pushes power to the camera?

Wil that work?

Thanks

[g8dhe]

Red and Black from the camera will normally be the power to the camera, the Yellow will normally be the Video from the camera. White could be a Microphone from the camera (not likely if a rear view camera) or could be power to LED's if there any built into the camera for illumination of the scene.