[Android Head-Units] skezza:
So, rooted my device earlier using the tutorial I linked earlier. It's a good solid method of rooting and it appears to survive reboots. Good start. However you will be constantly nagged to update the su binary. Don't. It unroots the device. This wouldn't be so bad but if you have Xposed running as I did earlier, you're in bootloop territory. Nothing that can't be fixed by flashing the stock ROM via recovery but a pain nonetheless.

Honestly, mine is nothing more than a £12 generic boot/trunk handle camera for E90's. Shipped from China it came with pretty much everything you need other than a set of decent instructions. I would say it's not a gimmick. Although it's angled down, I find this is more useful than if it was facing directly back. It gives me an idea how close my rear bumper is to the object behind. If it was straight, I doubt this would work. I'll take a photo tomorrow if you like.

I would say it's an hour or two's work at best. There are one or two issues you have to overcome but the fact I've already done this means I can pass onto you guys.

There are two key issues you'll have to deal with:

- Getting the cable through the 'boot of death' as I call it.

- The reversing light circuit only provides 11v.

So let's address the first one. Your RCA cable is a fairly chunky cable, and you need to get it through the rubber boot that protects the OEM wiring from water ingress etc. It's the rubber 'snake' on the right hand side. This thing is horrifically short on space and this will be your biggest problem. You need to get the RCA connector and cable through and it's not easy. Option 1: Shed loads of fairy liquid, silicone lubricant etc. Coat hangers and just time and effort. Option 2: Less fairy liquid, cut the wire and solder it back together. Option 2 is what I went for. If you can solder, it's easy and it makes perfect sense. Plus you only need to solder the yellow and black, we want to keep the red one for the next issue.

The second issue is the reversing circuit only provides 11v. When the car is off, this isn't so much of a problem as the camera can roughly function at 11v. With the ignition on, I suspect the 11v isn't as clean and therefore you get all kinds of weirdness with the camera. Eventually, the power system kicks in and cuts off the camera altogether. So you need a relay. Buy a cheap 4 pin relay and base from China, about £2. Wiring colours are usually useless, but what you need to know is:

Pin 87 - To Battery Live (fused please)

Pin 86 - To Reversing Light Live (black and blue on reversing light loom if I remember correctly)

Pin 85 - Ground (Brown on the reversing light loom)

Pin 30 - To Reversing Camera Live.

Connect reversing camera ground to same Ground as relay as well. Might as well.

Then you'll realise you still have the issue of running an extra wire from the battery for the relay. Not another wire through the boot of death. No ;) Remember the red wire? Strip back some of the insulation on the RCA cable, and break away the red from the cluster of three, solder some extension wire onto it and then run that directly to the battery, hiding it behind the trim so it's nice and tidy. The red switch wire will be by the RCA still up in the boot so you can solder that directly to the relay. Don't forget the fuse. That's it really.

Heat shrink the whole lot etc and you'll have a clean OEM like install.

I'll take some photos tomorrow to try and give an idea of how I went about it. I reckon the whole thing probably took 3 hours, but that's because I came at it like a novice. With these tips, it should be fairly straightforward :)