Wiring & Hardware Installation


The Car PC (carputer) is mounted in the trunk, so a power line of some kind needs to be run to the trunk. This can be done with the same steps as powering an amplifier using an amp wiring kit (with fuses, etc). I want to keep things simple, so I will be “splicing” the 12 V adapter. This is a more simple approach, in my opinion, because of several factors:  


  • The 12 V adapter is already rated for 120 W (The PC uses about 75 Watts)
  • The 12 V adapter’s power line is only hot when the ignition key is turned
  • The wire run to the trunk is fairly straightforward



The Civic after I’d vacuumed, washed and waxed it. I’d recommend doing the same (except for maybe the waxing), if you plan on doing any kind of work on your car. I find it’s easier to work in a clean cabin, and I’m less likely to scratch something because I’m inclined to finish with the car in the same condition that I began with.





This centre console needs to be pulled back in order to remove the trim holding the 12 volt adapter.





First remove the shift knob. It took 9 turns on mine. Try to remember how many turns it takes for you, in order to keep the tension right (or to prevent you from over tightening and stripping the shifter)





Pull up gently but firmly on the trim around the handbrake. If it’s not moving, use a thin screwdriver or trim removal tool and gently loosen the edges.





The centre console needs to be slid back in order to access the 12 V adapter.





Push the seats forward and remove this screw (and its counterpart on the passenger side).





Two additional screws go into the floor near the handbrake. Remove them.





Another pair of screws are behind the shift knob.





Using the tip of a screwdriver, pop out the centre pin of the screws at the front of the console.





Pull back on the entire console to reveal the two screws below the DC adapter.





This part was a little tricky for me at first. You need to firmly pull straight down to unhook the tabs holding in the 12 volt adapter panel. Remove the connector attached to the adapter.





A lot of important wires run through the uncovered centre console. Be careful!





The black wire connects to the ground (body) of the car.





The yellow wire is the 12 V line, only powered when the key is turned. With everything turned off in the car, the power line is outputting 13.58 V.





Next I need to solder my own 12 V line to the back of the panel. Fortunately, no splicing is needed! Filing the shiny metal better prepares the area for soldering.





I used a stranded wire with similar gauge to that of the adapter. The adapter is rated for 120 W (10 amps at 12 volts)





Tape everything neatly.

NOTE: After I did all of this, I decided that I also wanted to add a power switch. Scroll further down to see those additional steps.





I’m choosing to run the wire in behind the glove box. Another suitable option is to run the wire below the glove box (this requires removing a different panel, but it is equally straightforward)






Pop out the two pins holding the glove box in place.






I used this as an opportunity to check up on my cabin air filter.






I replaced this filter relatively recently, so I just gave it a quick vacuum to remove some debris.






Snap back in the newly soldered 12 V panel into the car. I ran the wire behind the glove box and zip tied it neatly to an existing set of wires.

It is important to keep things neatly tied behind the dashboard.





Remove the additional trim along the passenger side of the car.





This black wire was already in place, and I made use of the tape already there to secure my own red wire. Sometimes the white tabs fall off when removing the trim, but they easily lock back in.





Remove the trim around the seatbelt.





We need to get this wire into the trunk. Removing the rear seat is an option, but instead I use a an old flexible flag pole from a kids bike to fish the wire under the seat and into the trunk.





Remove the two screws securing the trunk lining in order to access the wire tunnel in the trunk.





At this point, I’ve introduced the USB keyboard cable (gray). This cable contains four wires, exactly what we need for the USB connector.





Run the keyboard wire back up to the front passenger seat. I decided to have the wire exit near the recliner handle, run below the seat and up into the cup holder area where the driver can access the keypad.





Tie the wires in place along the run.





Next we install the ground point. I found an existing hole in the trunk in which to connect to ground using a bolt.





I filed two washers and sandwiched the ground connector in between. The filing ensures clean electrical contact.

This ground connection point can also be used for additional electronics projects down the road (make sure you tape off the end of any open wires to prevent shorting).





My original plan was to splice the USB connector and keypad at both ends of the extension cable. This proved very difficult, because the keypad wires turned about to be very small and packaged with two wires paths per cable. I couldn’t get a reliable connection, so I had to install a new USB cable.





The cut-open keypad with the new USB cable attached. This cable was made of much nicer and thicker wire. I had to use an ohmmeter to map the pins to the correct pads. The cabin end of the extension wire now has a female USB connector, so the keypad can be easily removed/replaced.





As for powering the Car PC, I’ve decided to use an inverter. You may wish to purchase a DC computer power supply, which would allow you to power the computer directly off the DC 12 V line. This option is more expensive, however.

 I created a homemade 12 V adapter for the inverter to plug in using an old water bottle. The flat ring is foil-covered cardboard, with a metal screw in the middle as a steady connection point. The sides consist of a separate ring of aluminium foil, connected to the ground line.





The inverter (and subsequently the computer) power up automatically when the ignition key is turned. However, I decided at the last minute that I want to have a handy in-dash bypass switch.

I purchased an SPST switch from radio shack rated for at least 10 amps. The civic fortunately has a pop-out trim piece which is perfect for housing the switch.





I drilled a large enough hole to allow the switch to snugly screw in.





I decided on a left/right on/off orientation. Just a matter of personal preference.





Unfortunately, I thought of installing this switch AFTER I installed the original power line. This required some extra soldering.





Again, tape everything up neatly.





Looks pretty good!





I locked all of the interior trim back in place, however I found this small piece lying behind the driver seat. Anyone able to identify this for me?





Finally, we can mount the computer in the trunk! I’m using Velcro straps to attach the computer to the carpet. There are better methods of mounting, but so far the computer has not moved an inch while I’m driving.





If you desire a more secured carputer, cut some slits in the rear seat and run the Velcro straps around the metal bar in the back seat.





Make sure the inverter is fastened securely.






The FM transmitter (on the right) is connected to the output audio jack and broadcasts on 88.7 FM.

See the next page on the FM Transmitter/Sound options for an explanation of how I eliminated the batteries and power the transmitter via USB.





Some last minute software troubleshooting requiring the use of a monitor. It turned out there was a conflict with connecting the keypad via USB. I fixed it by using a PS2 adapter to bypass the USB port.





With everything mounted!





Next Page

1. Introduction

2. Computer Software & Setup

3. Wiring & Hardware Installation

4. Powering FM Transmitter via USB / Other Sound Options



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