How-To: Wire Switched 12V


Established Member
Sep 12, 2013
Martinsville, VA
Here’s just a quick write up on how to get a switched 12v source on our 2011-2014 Mustangs. For my particular install I was wiring my nitrous arming switch.

· ATM Add-A-Circuit – Found at any auto parts store.
· Soldering Iron
· Electric Solder
· Desired Gauge/Color Wire
· Heat Shrink
· Zip Ties


1. On the Passenger Side foot well, located the plastic cover on the right hand side and pull on the tab to remove it.


2. Move the 2 brown flaps covering the fuse box and tuck them out of the way. (If they haven’t been removed, there will be 2 pieces of tape holding the flaps that cover the fuse box)

3. Remove the fuse box cover by pressing on the 2 tabs.


4. Remove Fuse #33 “Not Used” 10A spare.

5. Solder your desired length of 18ga wire to the Add-A-Circuit wire. Length depends on where you are trying to reach. I used about 2-½ ft. to be safe. Cover your solder with heat shrink tubing. You may also use butt connectors, but I wanted to ensure that I had a good connection because I was dealing with nitrous.


6. Take your Add-A-Circuit and place a 10A fuse in one of the two slots. Then place it in the #33 slot of the fuse box.


7. If you are wiring your switch to the removable panel inside the center console, follow the next steps. If not, run your wire to your desired location.

8. Twist off your shift knob by hand, you’ll need a good grip. Sometimes these can be a pain but mine wasn’t bad.

9. Open the rear compartment of the center console. Carefully pull up on the rear of the center console, right behind the cup holders. Once you pop the rear of the console out, move your way forward towards the dash, carefully lifting on the console.

10. Lift the center console up and disconnect the electrical connection to the Traction Control, Hazards, and Trunk Opener. Also guide the shift boot up and over the shifter.


11. Route your wires under the carpet, beside lower part of the dash next to the transmission tunnel, and up into the underside of the console. Then tuck them nice and neat out of the way and up into the rear compartment by removing the small removable panel. (Picture is a view from the dash towards the rear of the car)


12. Reinstall the center console, ensuring you reconnect the electrical connection to your TC, Hazards, and Trunk. Place the fuse box cover of the fuse box, mine would not seat all the way due to the wire running out, but you can take a small file or drill and make a U on the cover to allow it to fully seat on the box. Put your 2 flaps over the fuse box and attach them together with the Velcro. Then put your plastic panel back on and take one last look to make sure everything is tucked out of the way!
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Established Member
Jun 16, 2012
Camarillo, CA
Nice write up. I did the same thing with my nitrous setup. I wired a the Nitrous Outlet switch panel, and I didn't have everything nice and tucked out of the way when I put the center console back together. I kept blowing fuses and couldn't figure out why. After a few agonizing hours, I found that my hand brake had pinched the casing on one of the hot wires in the console and was randomly shorting everything out. I'm lucky nothing started on fire.

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