Subaru & Toyota OEM
Many recent Subaru and Toyota head units (HUs) with a video screen (with or without navigation) include rear camera capability. Most are already wired to the car's reverse gear signal, and will begin automatically displaying the camera image after you connect a camera. This page covers models with a 16-pin socket for the rear camera input. See list of applicable HU models at the bottom of this page.
Camera Input Video Standard
The head unit's camera input requires a normal composite video signal. It is always NTSC, even in countries that use PAL for TV. The HU has no configuration option to use a PAL camera. You must choose a camera that outputs NTSC.
Note: Many cameras being sold on eBay are listed as "NTSC/PAL." In most cases, that only means that the core camera element is capable of generating either format. However, the factory configures the camera for one particular format during assembly. The camera's video format is not user-selectable. It is also not automatic — a camera can't tell what kind of monitor you've connected it to. Verify with the vendor that your camera will output NTSC. If the vendor claims it can do both, ask them how you can configure it (they won't have an answer, since it is not possible).
Parking Guide Lines
North American Subaru navigation models made by Fujitsu Ten always add parking guide lines. You can use dealer service menus to adjust their position, but nobody yet has found any option to turn them off. So you'll want a camera that does not generate its own guide lines (or where they can be disabled). Check with your camera's vendor or manufacturer before buying.
Australian FT nav models do not add the parking lines to the display while in reverse (even though they are shown and can be adjusted in the dealer service menus). The TAS300 and BeSpoke HUs also do not add lines. So on models that don't add lines, you might want a camera that does have its own lines. Again, check with your camera's vendor or manufacturer before buying.
All of the HUs add warning text (e.g., "Check Surroundings Before Backing Up" or similar). That text cannot be disabled.
The HU decides whether a camera is connected each time you turn on your ignition key (i.e., when the HU receives +12V Accessory power). If it detects a camera, it will enable the rear camera feature and automatically display the camera's video whenever you shift into reverse. Conversely, if it does not see a camera during boot up, the HU will decide to keep the rear camera feature disabled.
How it works:
For this reason, you cannot power a camera from the reverse lights (otherwise you would have to make sure you shift into reverse immediately after you turn on your key). You will need to power the camera one of these three ways:
Head Unit's 16-pin camera socket
16-pin socket (on rear of the HU), with pin numbers:
The HU connects the CGND pin to ground internally. You do not need to connect anything to this pin for the rear camera feature to work. You can use it to provide ground (along with the +6V pin) to a camera that has its power and ground leads at the HU end of its long cable. You may also use the 6V and CGND pins for a relay (details about that below).
Picture of rear of Impreza's factory 16-pin harness:
The GRAY wire is the parking brake signal (color is VIOLET/RED in Foresters, RED in some Toyotas).
The factory harnesses in Impreza, WRX, and STi models have an extra wire looped between pins 4 and 5 (YELLOW wire in picture) which Forester, BRZ, FR-S, and GT86 do not have. I don't currently know the purpose of that wire.
HU's 6 Volt Camera Power Pin
Recent Subaru and Toyota OEM cameras are powered from the factory HU. The HU has a pin on the camera socket which supplies +6 Volts DC. Powering a camera from the HU's 6V lead will make your installation easier — you won't have to tap into another +12V wire for the camera, and the HU will turn on the camera only when needed.
Camera's Power Input
Many cameras actually operate internally at 3.3 or 5 Volts. The camera's harness often includes a molded plastic "nodule" that contains a voltage regulator, which reduces 12 Volts down to the supply voltage that the camera element requires.
The Rydeen DUO and MINy are confirmed to work from 6V (and have been very popular with Subaru owners).
For other cameras, check with the manufacturer or your vendor to see whether it will work from 6 Volts. However, even when a camera manufacturer lists "12V" on their specifications or says that the camera requires a minimum of 12V, people have discovered that many cameras actually do work from 6V.
If you're unsure about your camera, I recommend that you test it from 6V. You can use a good 9V battery as an initial test, then try four 1.5V batteries in series (end to end). Also be sure to test in low light. People have run across some cameras that look OK from 6V in daylight but have noticeable degradation from 6V in dark (and needed a slightly higher voltage).
In some poorly-engineered Chinese cameras, the voltage regulator can run extremely hot from 12V. The cameras were obviously designed to be powered for brief periods of time, from the reverse lights. See this YouTube video — super HOT car backup camera from ebay. Powering the camera from 6V will help reduce the heat.
Some cameras have two branches on their power lead — one near the HU, and another near the camera. The manufacturers include the second branch so that you can power the camera from the reverse lights (via the lead near the camera), and also pass the reverse gear signal to your head unit (via the lead at the HU end of the long video cable). However, since the wires are electrically the same, you can power the camera from the branch near the HU. Several Rydeen models and many Chinese models are configured this way. If your camera has the dual branches on its power lead and works from 6V, use the one near the HU. Insulate the branch near the camera — do not use it for any purpose.
Using a Relay
With a camera that requires more than 6V, you may still want to use the HU's 6V pin with a relay, so that the camera will only be powered when the HU needs it.
Choose a small relay with a 6 Volt coil. It only needs two switch contacts, which close when the relay is energized. This type of switch is designated SPST (Single Pole Single Throw). The relay's switch contacts need only be rated to handle 1 Amp (since most cameras draw less than 1/2 Amp). I don't recommend using a large 30 Amp automotive relay, since they may not work reliably from 6 Volts, and they will be audibly loud.
(Wiring diagram to be added soon)
Source for +12V Accessory Power
BRZ, FR-S, and 86 models all have an unused factory harness behind the HU that provides +12V Accessory (key-switched):
I offer an Option Connector harness which fits that factory "Option Connector" plug (e-mail me for more information).
Parking Brake Input
On all of the OEM HUs I've seen with the 16-pin camera socket, one pin is an input to detect the car's parking brake switch. All Subarus and many Toyotas have a factory harness with a 16-pin plug with a wire for that signal. Some cars (for example, those with the BeSpoke HU) have no 16-pin harness.
The parking brake signal is used to block display of movie video (from USB movie files or DVD) or the aux video input. It may also be used to temporarily disable certain menus that the car or HU manufacturer deemed to be too distracting for the driver to use while the car is moving.
Most of the HUs have a pin on another harness with the car's Vehicle Speed Signal (VSS). The HU also uses that to detect motion and block movie and aux video and some menus. Navigation models can also use GPS for the lock out.
The HU's parking brake input does not affect the rear camera function. It's just that somewhere along the line, Toyota decided to place that signal on a pin on the same socket used for the rear camera.
If your car has an existing factory 16-pin harness with the parking brake signal, you'll need to do one of two things when you add a camera:
Because the HU also uses VSS (and possibly GPS), option "A" has essentially no impact (other than allowing the camera harness to be simpler, and thus less expensive).
Reverse Gear Input
In most cases, the car's reverse gear signal is already connected to the HU (on a 28-pin harness). On those cars, you only need to connect a camera for the rear camera feature to start working automatically.
FR-S models with the BeSpoke and Pioneer ADCP-W12U T1818 (and possibly some other HUs) do not have the reverse gear signal connected. In those cars, you must also add a new wire into the empty slot on the car's 28-pin harness plug (pin #2). Ideally, you want the wire to have the proper style of terminal to snap into the empty slot on the factory harness plug. You'll need to splice the other end of the wire into the car's reverse gear signal, typically located in the driver's footwell.
You can check whether the reverse gear signal is connected via the HU's dealer diagnostic menus (rather than needing to remove the HU to look at the 28-pin harness). Tip: You must turn your ignition key to the "ON" position for the reverse lights circuit to work, but you do not need to actually crank the engine.
Using an OEM Camera
Most of the Subaru OEM cameras have a short harness with a proprietary plug. They are intended to be added to cars that have a pre-installed camera harness in the trunk or tailgate. To use one of those cameras in a non-pre-wired car, you would need to extend the camera's harness from the rear of the car to behind the HU. And before you ask -- no, I do not have a harness that fits any of the OEM cameras' plugs.
If you would like to avoid cutting off the OEM camera's plug, the OEM trunk/tailgate harness has the matching socket. The last segment (with the camera socket) may be available as a repair part, but they are very expensive. The harness is fairly short, so you would still need to extend it to the front of the car.
Note: If an OEM camera is an option for your car, that should mean that your car is pre-wired. Check with your dealer to see if that's the case. If you want to add an OEM camera to a pre-wired car, you won't need an aftermarket camera harness.
Test Your Camera Before Installing!
Many people have purchased cameras that did not work — either because they were dead out of the box, had the wrong video format (PAL instead of NTSC), or their signal was not compatible with the factory HU's rear camera input. See this post for an example of a camera whose signal was not compatible.
So before you install your camera, I strongly recommend that you test the camera on a TV or monitor that has a composite video input, so you can quickly find out if the camera has any problems.
Next, test your camera connected to your factory HU (via my camera harness) — again, before you spend any time installing the camera's long cable (and especially before you drill holes, cut wires, etc.). You'll want to know if the camera has any problems while it's still easy to pack up and return to the vendor (and your next camera could require different holes).
As an added precaution, especially for a camera with a limited range of angle adjustment, I suggest temporarily placing it as close as possible to your planned mounting location — use some double-sided tape, a glob of putty, a helper, or anything else you can come up with — and check the view on a monitor or your HU. The goal here is to verify that you'll be able to adjust the camera angle so that it gives you the view you want (image right side up, not showing too much bumper or pavement straight down, and not too much sky).
If your camera is not from a name brand (Kenwood, Clarion, etc.), you might even go so far as to temporarily mount it on your license plate or wedged in your rear window and drive around with it several days to make sure it doesn't die.
16-pin Camera Harness
For information about my 16-pin camera harnesses, including pricing and how to order, see this page.
OEM HU Model Numbers
These HU models have the 16-pin camera socket and have been confirmed to work:
Those model numbers (except the Aisin) are the ones printed on the front of the HU (typically found in the upper left or lower right corner). Undoubtedly there are many more. If you know of another that has a 16-pin rear camera socket, please let me know so I can add it to this list.
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