How many times have you been in the car with the kids, or your homies, or that hobo you picked up hitchhiking, and suddenly everyone and their brother needs to charge their phone... o_O and then to make matters worse you have to stretch a cable all the way to the back seat to be passed around like two scuba divers on one tank of air. and of course you didn't need the 5ft cord, the 12inch one is fine....now you have a voltage deficient hobo squeezing between the front seats so he can check his status updates while his phone charges.....
Let's fix that..
Step 1: Finding a Power Source
So the idea here is that we don't want to run wires from the front of the car. but most of the wiring running to the back is for the signal light....let's not mess with those.
Fortunately there is an alternative for most of us, the trunk light.
Now in my case, and I suspect yours as well, my trunk light uses a 12v bulb. Perfect! That's the same voltage as your cigarette lighter!
Step 2: Connecting Your Charger
Once you know where you are getting your power from you need to convert it to something you can use. I wanted to keep this simple.
Since the trunk light uses the same 12v as the cigarette lighter then we can just use a regular car charger.
I am using a Belkin car charger I got from Wall-mart. but any charger will work for this. I do recommend a 2.1 amp charger just cause the extra wattage does charge the phone faster then the standard 1amp veriety.
Now, to wire this up is really simple. Red is positive + and Black is ground/common. If you look at the picture, the tip is positive (red) and the side is ground (black). Most of these have two side contacts but both are ground.
In my case I dismantled the light fixture and incorporated the pieces but honestly you can just run long enough wires to connect the contact from the light bulb to the charger.
Step 3: Cut a Hole
If you look at the previous step the charger I am using flairs out at end. so it was perfect for this I just cut a small whole in the rear window ledge and pressed the charger in. But as you can see it is metal under the felt. There was already a hole
Step 4: Finishing Up
Once you have your leads (wires) soldered to the car charger thread it through the whole and connect them to the contacts for your light bulb. MAKE SURE YOU CONNECT RED TO POSITIVE AND BLACK TO GROUND!!!
And that's ......
Step 5: One More Thing
You also might want to ground out the latch switch. or else you can only use your charger when the trunk is open... like when the light is on.