Moving this from the end of a thread discussing the opposite scenario
OK an update to this... If you are replacing your Mazda head unit (due to the crap handling of the USB, or any other reason), you CAN keep your factory rear-view camera and use it with your new aftermarket head unit. Having just done this with my car today, I can tell you what works for a 2014 CX-5 Touring (at least).
Basically, you can follow this German's guys diagram to do it, here:
http://www.mazda-forum.info/mazda-c...ine-incl-navi-nachruestbar-31.html#post478862. Except he shows a switching regulator as a 6V power supply, and as I said above, I would stay away from those and use a linear regulator instead.
Counter to all intuition and accepted color code usage (Huh Mazda??), the wiring to the factory connector is as follows:
- the Red wire in the connector (6C) is the negative video signal
- the Black wire (6D) is the positive video signal.
- the White wire is the 6V supply to the camera
- and the black shrink-sleeved braid wire is the ground (0V supply)
I can tell you that if you swap the video wires, such that red is positive (as I did originally), you'll get a very corrupted video signal... virtually total noise.
Anyway, here's a (hopefully) clear picture of what you have to wire to retain your factory camera for use with an aftermarket head unit, This is looking from the perspective of inserting pins into the factory harness plug behind the radio. By the way, this connector has pins on 0.1" spacing, meaning you can use common PC double-row header strips as a plug (like these:
http://www.vetco.net/catalog/images/VET-HEAD-DR-8-1.jpg). Just cut off a length of 3 (by 2) pins, and remove the two center ones. The four outer ones will plug in perfectly!