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Discussion Starter #1
I'm trying to install a chinese reversing camera to my 2017 M6. The item came with a cable but the connector doesn't fit in any of the connectors behind CMU... I have contacted the seller but trying to make the chinese sellers understand my problems is PITA!


I have tried to collect info from workshop manuals and other forums. So far I have managed to find out where the video signal is supposed to be connected in the CMU. I don't have the wiring diagrams of M6 but I have founds this pinout diagram of M3 and I believe they share the same pins and connectors. The connector for the camera is the white with 28 pins.



So according to this pinout diagram 1A = VIDEO +, 1B = VIDEO GND, 1C = CAMERA POWER (+) 1D = CAMERA POWER GND. The original camera is powered with 6V so I assume there is 6V voltage between 1C and 1D.


After pulling my CMU out I noticed that there is already cables connected to the 1A and 1B pins. This got me thinking that maybe they already have routed the cables for the camera. I checked the wires in the trunk area but couldn't see any loose cables. In the workshop manual's camera diagnostic section reads this:

  • Inspect the following wiring harnesses between the audio unit and rear mount camera.

    • Terminal 6A (4-pin, power)—terminal A (5-pin, power)
    • Terminal 6C (4-pin, GND)—terminal E (8-pin, V-GND)
    • Terminal 6D (4-pin, COMPOSITE)—terminal C (8-pin, COMPOSITE)
    • Terminal 6B (4-pin, signal GND)—terminal E (5-pin, sield GND

(edit. I found out that this part is from pre MZD Connect system)
When I peeled away the left side garnish in the trunk, I was able to see a cluster of cables. I wonder if the cables for the camera are already in there.Has anyone else installed an after market reversing camera to a 3rd gen M6?



I would be thankful if someone could confirm these pinouts (1A,1B,1C,1D) of the 28-pin connector behind the CMU!
 

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You may have to tap into the wires. I have a aftermarket radio and I purchased the adapter, for the OEM backup camera to work with the aftermarket radio. But I believe the same adapter works for the OEM radio. I am not sure if you need it.

AX-MAZCAM Retain OEM Back-up...

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Discussion Starter #5
Looks like it would be too much trouble to try to find the correct wires. Luckily there is an adapter cable available. I'm going to order one for easier installation. This cable doesn't have the voltage output so I have to find a way to feed 6V to the camera.
 

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Looks like it would be too much trouble to try to find the correct wires. Luckily there is an adapter cable available. I'm going to order one for easier installation. This cable doesn't have the voltage output so I have to find a way to feed 6V to the camera.
With the harness i posted above, the camera is always getting power. When the radio is on. Just tap into any 12v fused and get a 6v step down reg.

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You might not need a 6v step down regulator. The OEM camera is 6v. Your aftermarket camera prob regulates its own power with the harness.

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Discussion Starter #8
I have now spent couple of evenings trying to figure out how to install this camera and I am exhausted... The new connector I got was wired in a strange way. The "video signal +" was in the right place but the "video signal gnd" was in the "rear camera power supply gnd" terminal. I had to solder the "video signal gnd" to the right place. The pins can be removed by pushing a small flat object in the hole below the connector but I couldn't find anything that would fit in there.


The adapter cable was ready and I began to test if everything works. After connecting everything I noticed that if the engine is running and I switch to reverse, the leds in the camera light up but there is no signal. After shutting down the car the leds were still lit up. Fortunately I noticed it because it could have drained the battery in a long run!


So I have no video signal but leds are working so I have to start the fault diagnosing process. I took everything in to my garage and hooked the camera in to my small chinese 7" TFT monitor. I powered the camera with my adjustable lab PSU. The camera is supposed to be 6V camera just like the OEM one so of course I'm feeding it with 6VDC. "No signal" reads in the monitor... I had another cheap camera so I wanted to test the monitor and the cables with this second camera. Everything was working with this camera so I begin to think that maybe the new camera is faulty.


I try to message the seller and luckily he responds quickly. He believes I have chosen the wrong source from my test monitor because he can see it has 2 video inputs from the photo I sent him. I tell him that the monitor works well with another camera. Next he asks me to connect the camera to 12V. I ask him if he is sure about that because it is supposed to be a 6V camera and it even reads 6V in the cable. So I proceed to connect the camera to 12V instead of 6V and boom, there is the video signal!


Now I have to figure out how to get 12V for the camera from the wiring of the car. I guess I'll try the reversing lamp.
 

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Discussion Starter #9
Ok, my second attempt was not very fruitful either... Now I have connected the camera to the reversing light lamp wires. I confirmed it's connected to 12V and is not shorted. So far so good. I connected the adapter cable and plugged in the composite video connector. Turned on the engine and shifted to reverse. No video...

I took the cables out again and connected the composite video to my old but trustworthy TFT monitor. Engine on, reverse gear and I can see the video from the camera in the TFT monitor. So the camera works and it outputs video signal. I confirmed that the adapter cable is ok and used a multimeter to check the continuity from the video connector to the pins. All good.

Once again I put everything back together and pray for the best but no. No luck for me. I have tried to soft reset the CMU on neutral gear and on reverse gear. Nothing seems to help and now I'm facing a wall here. I have no clue how should I proceed from here. I'm already thinking of taking the car to the shop and get the OEM reversing camera installed...

Can someone figure out if I'm forgetting something?
 

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Discussion Starter #11
Guy989: I had that exact harness but it didn't fit. The harness I posted does fit and has pin order just like in the pinout diagram above.



I was able to dig some more info from the www so I started to reverse-engineer this whole back up camera thing and wiring of it. I found some OEM rear view cameras listed for sale on ebay. Those were for Mazda models with MZD Connect and the 7" screen. These headunits are the same in all Mazda models and so are the connectors and pinouts. The OEM camera has a connector with 4 wires. An OEM harness for these headunits was also for sale on ebay. There's not very good pictures of it but I was able to tell that it connects in series with the 28 pin connector just like the harness I bought. There is also a long cable attached to the harness and that part goes to the trunk. In the end of the cable is a connector with 4 pins.


Now I'm 100% sure that the camera is connected with those 4 wires from the 28 pin connector (1A, 1B, 1C, 1D). 1A and 1B are for the video signal and 1C and 1D are 6 volts for the camera. I came across with one forum post that clarifies the operation of the camera. I can't find the exact post anymore but the guy was telling that the camera must be ON and feed video signal to head unit before it fully boots up. Headunit is supposedly checking the camera connections during boot and disables the camera functions if it can't find one connected. Today I measured the 6V from the 1C and 1D even after the engine was shut down. There must be a constant voltage going to the OEM camera or then the 6V is cut with a timer or something. This 6 volt was not enough to power my camera, (which I thought is actually 6V in the first place) so that's why it didn't turn on. After switching the camera in parallel with the reverse lamp it was not powered on when the head unit was booted for the first time.


Maybe I should try one more time and power on the camera with external PSU before turning on the car and see if the head unit then recognizes it. This problem is clearly not caused by faulty equipment but a logic behind how the camera works with the head unit.
 

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Discussion Starter #12
Houston, we have video signal! This began to feel like a battle between human and machine. I was already about to give up but I could not let the machine win!


Once I connected the camera to the cigarette lighter it started to show the video in the head unit. I had to restart the HU once to make it recognize the camera.


Now I have to find a way to wire 12V to the camera so that the voltage is up immediately after turning on the engine. One option could be the register plate lamp. I've read that some lamps in cars are powered with pulse width modulated signals and that would be bad for the camera. I could also run wires directly from behind of the cigarette lighter plug. Then I think it would be good idea to add a fuse in the line.
 

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Discussion Starter #13
I will continue my monologue in hope that someone finds this info useful in the future. I'm finally making progress here. Powering the camera from registration plate lamp was not very good idea. I thought the registration plate lights are constantly on but apparently they shut down with all other lights when the light sensor thinks it's bright enough to turn off the lights.


So I was reversing out of my carport and the head unit was displaying the video of the camera. Once I was out in the sun light the screen went black...


This is typical example of my luck when I'm installing something so I'm kind of used to making things over an over again... I think I'll leave everything as it is for now and continue finding a better power source on my summer holiday.


To sum it up, chinese aftermarket camera can be installed to the head unit we have in 3rd gen Mazda 6 (2015->)
 

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I will continue my monologue in hope that someone finds this info useful in the future. I'm finally making progress here. Powering the camera from registration plate lamp was not very good idea. I thought the registration plate lights are constantly on but apparently they shut down with all other lights when the light sensor thinks it's bright enough to turn off the lights.


So I was reversing out of my carport and the head unit was displaying the video of the camera. Once I was out in the sun light the screen went black...


This is typical example of my luck when I'm installing something so I'm kind of used to making things over an over again... I think I'll leave everything as it is for now and continue finding a better power source on my summer holiday.


To sum it up, chinese aftermarket camera can be installed to the head unit we have in 3rd gen Mazda 6 (2015->)
Tap into the reverse light for the camera or a constant 12v source

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Discussion Starter #15
Tap into the reverse light for the camera or a constant 12v source

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I tried the reverse light first and it didn't work because the camera must be powered on simultaneously with the head unit.


With 12V camera a constant 12V source is the only option. With 6V camera the pins from the head unit can be used but there's a chance that the camera could drain the battery if the 6V from the head unit is not turned off with a timer. I have not confimed this yet. (That's where the OEM camera get its power from.)
 

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You could look into getting a relay and using the 6v as a trigger. At this point it would probably be better to just get a 6v camera either aftermarket or from a wrecker.
 

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I tried the reverse light first and it didn't work because the camera must be powered on simultaneously with the head unit.


With 12V camera a constant 12V source is the only option. With 6V camera the pins from the head unit can be used but there's a chance that the camera could drain the battery if the 6V from the head unit is not turned off with a timer. I have not confimed this yet. (That's where the OEM camera get its power from.)
With my pioneer radio and the OEM camera, it is ran off the radio, so I would say yes, that the radio loses power when the car is turned off. My USB off my radio aftermarket no longer charges, so you should be good to go there. You could always test the circuit with a voltage tester to be 100% certain.

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Hello Nobios,

i know it’s a couple of months ago you wrote this on this form but you
helped me a lot with this research , i was also struggling with an aftermarket camera.
After reading your research some things became clear for me.
i used a 12 V camera and a 24 pin connector with video plug.
238747


This connector must be plugged into the back of the monitor unit.
The two wires (Red /Black) are 6 V power cables for the camera.
in my case i had a 12V camera and could not use them so i picked an ACC + from the second connector in the back of the monitor unit.

238751




When you connect the camera you must program the camera by holding the NAV and MUTE button in the console for 10 seconds.

238750


First i had the camera powered with the reverse light ,it worked but if you turned off the car the camera was gone.
Now the fun was........ :
The MZD unit will check the whole system when you start the car for electrical users and will not see the camera because it’s not powered when the car is not in reverse!!
After i connected the camera to the 12V ACC the system will recognize the camera each time you start the car and the screen will be activated when you put the car in reverse.

I want to say: Thanks for your research and i hope that this Tech Talk would be helpful for other people.

BTW i am from the Netherlands, i tried my best to write this in English.
 
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