This is my first instructable and I welcome all constructive criticism.
A while back I bought a cheap DVR from China for my car. Well it lasted about a month so I guess I got what I paid for. I decided to get a true DOD DVR and tracked down their distributor to ensure I do not get another knock off. I am very happy with the DOD, the picture quality is much better and the camera is working flawlessly. I decided that it is time to wire it into the car properly. Usually the usb cable is pushed under the headliner but you still end up with the converter sticking out of the cigarette lighter. While visiting the various Subaru boards I learned that there is a power supply harness for the rear view mirror accessories. It turns out that almost every Subaru has the same power supply behind the map light pod.
The following is a very simple way wire in power for your DVR or any other accessory you need power for.
12v to usb adapter
inline wire connectors
flat head screwdriver
wire harness from old computer power supply
First step is to remove map light pod. Start by using a flat head screw driver to take off the clear cover of the map lights. Be careful not to scratch the pod. You can tape over the screwdriver to prevent scratches.
Now remove the two screws that are visible.
The map light pod will now hang down. Disconnect the harness by pushing down on the tab on the top of the harness.
You will see the power supply harness that you are looking for inside. It will be wrapped with foam and will have three pins. With my Impreza the centre wire is ground and the yellow with red stripe wire is power when the key is on. It is important to make sure you get the correct wires as you do not want constant power, otherwise you will slowly drain your battery.
I fashioned an harness by cutting up the harness for a computer power supply. You will only need two wires attached to two male connectors. I used a hacksaw and trimmed with an knife. The harnesses should fit together tightly. Test to make sure you have the polarity right!
Sorry about the poor pictures.
I bought a 12v to usb adapter for under $10. I removed the bracket and dust cover, then put one wrap of electrical tape around it so it would not rattle. You should wire up an inline fuse at this point. I used inline connectors to attach the adapter to the harness I made. Make sure that you wire up the adapter correctly. Read the instructions and use a multimeter to verify polarity of the power supply. Before I went any further I tested the setup with a cheap LED light.
Thread the usb cable through the opening and under the headliner. Leave just enough cable to connect to the camera. This would be a good time to verify that the camera is in the place where you want it. Coil up the excess cable, zip tie it, plug it into the adapter and push everything into the map light pod opening. Plug in the camera to make sure all is good. Put the map light pod back in place.