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AUX 12V Power Outlet

After getting the 12V power adapter for the LED desk lamp setup, I wanted to have easier access to power from the rear seat.  Like most cars, the Honda Civic has a power outlet in the front of the passenger compartment.  I'd shared access to that outlet with other devices.  It worked, but it was less convenient and there was the problem of a lot of power being pulled through one outlet.  On a given trip, we would have two smart phones, a dash cam, an LED desk lamp, and a laptop computer connected to that port.  We hadn't blown the 15 Amp fuse . . . yet.  I didn't want to keep pressing our luck.

This particular model had an option for an outlet inside the center armrest (called AUX accessory port).  Unfortunately, the previous owner didn't get that option.  Fortunately, the fuse box still had a slot for the AUX with power going to it and a 15 amp fuse installed.  It also turned out that the AUX is always on regardless if there is a key in the ignition.  I'd hoped that maybe all the wiring had been installed too and that I would just need to connect the two outlets I'd purchased.  That wasn't the case, so I had to do my own wiring.  Also, getting at the rear of the fuse box turned out to be much more trouble and possibly more risk than it was worth.  Inserting a spade connector into the fuse slot seemed the best option.  Not an ideal solution, but easier than running a wire to the battery.  12-gauge multi-strand wire is used throughout due to the short wiring length involved (under 13 feet).  The only exception is the gauge of the grounding wire (around 16-gauge) for the lighted power switch because it has a very low current draw.  A 15-Amp circuit breaker replaces the displaced fuse.

Glue from a hot glue gun holds the outlets in place.  That is a temporary measure since I'd been debating on installing the outlets on the rear doors instead.  Honda's design called for having the AUX outlet in the armrest compartment and it was certainly easier to install it there rather than in the doors.  The downside is that access is a bit less convenient for the backseat passengers.

Schematic of the circuit (drawn using Scheme-it an online circuit design application)


Completed wiring assembly for the outlets.  They are wired in parallel so that they both get 12 Volts.  The connectors are water-resistant with heat-shrink tubing extending over the wire.  I used that type of connector because it was the only kind that was available that has insulation over the connectors when I made the purchase.  None of the pictures show it, but we shrank all the tubing as part of the final installation.


Outlet wiring assembly coming out of the bottom of the center consule storage bin.  I used glue from a hot glue gun to hold it in place and to help keep debris from going through the hole.  Since the temperature at that location is unlikely to get hot, that type of glue seemed the best solution.


The two outlets are held on by glue from a hot glue gun.  It was a good temporary glue to make sure this location would work satisfactorily. Eventually, I will use a more permanent glue.


The lighted switch and circuit breaker.  I like circuit breakers better than fuses and I had the space for it.  I created the holes for these with a router bit on my Dremel tool and slowly sliced away plastic with an X-Acto knife until I had a good tight fit.


The underside of the switch and circuit breaker.


Completed wiring for the center console.  I used conduit whenever practical to help protect the wires.


Detail of the wiring for the switch and circuit breaker.  The green/black wire is for the ground for the lighted switch.  The switch must have a ground for the light to work. The spade shown without a connector is for the hot wire coming from the fuse box.


Path of the hot wire from the fuse box.


More of the hot wire path from the fuse box.  It's hard to tell what's OEM and what's my wiring in this picture and that's the way I want it.


The hot wire coming around to the center console.


The grounding wires.  I placed conduit around these before putting the center console back in position.


The center console reinstalled with power going to the outlets as can be seen from the illuminated LED's.


Completed installation showing the power switch and circuit breaker.  It's easily accessed and visible regardless of the postion of the parking brake which will lessen the chances of it being accidentally left on.