Mod: Add Constant and Accessory Power Outlets

[NH_T4r]

Here’s how I added power outlets and USB ports to my 4th-gen 4Runner. Unlike most of the mods, I found here, I wanted a combination of switched and constant-power outlets.



Specifically, I wanted to have the factory power outlet continue to be controlled by the ignition key (“accessory power”)… for my GPS. I only need that powered up when I’m driving.



The new power outlets are for charging my cellphones and Bluetooth devices. I want them to charge when the car is running (accessory power), but also have the ability to charge them when the car is off (“constant power”).



Rather than having these new outlets draw power all the time, I have the constant-power controlled by a rocker switch in the center console.



To summarize: the new outlets get power when the car is running, OR when the rocker switch is On; otherwise they don’t get power. The factory power outlet remains unchanged.





This mod uses parts and info from several other threads, plus a few extra diodes, to complete the build.



Step 1: Remove the center console cover that goes around the shifter.

It’s surprisingly easy. Instructions are at:How to Remove the Navigation Head Unit from a 2003 Toyota 4Runner


Step 2: Get constant-power over to the center console.

I purchased a device that many call an “Add a Circuit,” from Autozone ($12). Mine was listed as a “Cooper Bussmann/ATM fuse tap” Cooper Bussmann/ATM fuse tap (BP-HHH-RP) | Fuse and Accessories | AutoZone.com This is what it looks like:

To decide where to put it in the fusebox, I used a voltmeter to find an empty fuse location that had constant power. In my case (2007, SR5, no Aux power, no seat heaters), it was in the location shown:




The only tricky/confusing part is that I didn’t get power when I first inserted the Add-a-circuit. After some head-scratching, I realized that the device is directional… I had to remove the Add-a-circuit, and insert it pointing the other direction.


I connected a wire to the end of the Add-a-circuit and snaked it over to the center console opening.


Note: For the duration of this build, keep the Add-a-circuit unplugged from the fuse box. Remember, this is constant-power and you’ll find that you will cause a short with your screwdriver and have to replace the fuse if you don’t.


Step 3: Insert switch.

I purchased a lighted toggle switch from oznium for $12 (Scion OEM Style Lighted Rocker Switch). I got the amber, so it would match the lights on the dash.

I popped out one of the blank covers, and inserted the switch. It didn’t quite fit (the switch is a little big), but about 30 seconds with a file made the inside of the opening a bit bigger, and the switch now fits snugly in place.


Note: From above, the switch looks good. From the side, you can see a slight gap between the switch trimplate and the center console cover. Given the low price, I don’t mind.




Step 4: Insert the new power outlets in the center console bin

I purchased a Bestek “Four way socket adapter” (two-outlet and 2-USB) from AmazonAmazon.com: BESTEK car cigarette lighter socket usb car charger Cigarette Lighter adapter dc to dc charger usb car adapter socket car splitter adapter 4 way plug socket usb outlet four way car splitter charger: Camera & Photo for about $12.

I snipped the cigarette-lighter adapter off the end, so I just had to thread the wire from the storage bin into the center console opening.


Using a drill and a bit just larger than the cable (about ¼”), I drilled a hole from the bin into the center console opening, and threaded the wire through it.


To prepare for wiring, I bared the wires (inner is positive, outer braid is the ground).



(cont)

 

[NH_T4r]

(cont)

Step 5: The Circuit

Perhaps the only novel part of this mod is to include diodes to allow the new outlets to draw power from both the accessory power as well as the constant power.


The reason that diodes are needed is to prevent the current from flowing from the constant power wires back into the accessory circuit… and powering everything (including the factory outlet and my GPS) from the constant-power.


Diodes only allow current to travel in one direction, so they are perfect for this application. Here’s a picture of an appropriate diode (the 1N5404 from Radio Shack, $1.99) 3-Amp Barrel Diodes : Diodes | RadioShack.com

Note: Because diodes allow current to only flow in one direction, the direction you insert the device matters. The diode will have a line on one end (the right end, in the picture above). The line end goes on the negative side of the device (for current to flow). It also corresponds to the line on the end of the triangle on the circuit diagram (ie: the end with the line goes toward the Bestek device in this application).

Nearly any diode will work (you don’t need the 1N5404 that I used). Make sure it is rated for more than 12V and more than 1.5 Amps.


Here’s the circuit diagram:


Step 6: Wiring

To connect to the factory power outlet, I just scraped off some of the insulation, wrapped a wire around it, and soldered in place. Note that you don’t have to cut the original wire (the white/silver, in the picture below; just scrape some of the insulation off it). Once soldered, I wrapped it in electrical tape, and it’s all set.


I tapped into the factory power outlet wires immediately adjacent to the factory power outlet:


To connect the diodes to the wires, I did the same thing – stripped the insulation off the end of the wire, wrapped it a few times around the end of the diode, and soldered it to make sure I had a good connection. Then I wrapped with a bit of electrical tape (I was out of shrink tubing) for insulation.

Step 7: Final assembly
I used double-sided sticky tape to securely mount the Bestek device in the storage bin (although it fits pretty snugly on its own).


Step 8: Testing and troubleshooting
To test the circuit, leave the Add-a-circuit unplugged, and:

• Confirm that the new power ports do not have power when the key is removed.

• Confirm that the new power ports have power when the key is inserted and on “accessory” and confirm that the LED on the switch is off.


Remove the key, turn the rocker switch to off, and insert the Add-a-circuit into the appropriate location in the fuse panel.

• Confirm that the power ports do not have power, and the LED on the rocker switch is off.

• Confirm that there is no power to the factory installed power outlet.

• Turn the rocker switch On, and confirm that the new ports have power, that the rocker LED is on, and that the factory power outlet does not have power.


If you have problems with these tests, the most likely culprit is a reversed diode.


Good luck!

 

[ddnww]

I was just thinking yesterday how I hate the fact that the power cuts off when the ignition is off.

 

[matthewkristof]

i really like what you did with this mod distinguishing the constant vs ignition only. well done.

i did something similar...i hooked up a power unit that had usb ports and hid it underneath the panel that holds the shifter knob (right in front of the center console). i ran two usb cords to the back seats through the floorboards, and plugged in two iphone/ipod connectors, which are anchored to the driver and passenger seats. i hooked this up to the stock 115v switch (cause i too like the amber look).

one of my next mods is a constant power using an add-a-switch, and i think i'll be using your idea on connections!

 

[Flynnster]

Reviving a very old thread here, but I'm a bit confused on why this ties into the existing 12v power. If you left that alone, and added a circuit to the fuse that has constant power, wouldn't all the new ports operate the same, on all the time unless the switch is turned to off?

 

[amy2brno2b]

Reviving a very old thread here, but I'm a bit confused on why this ties into the existing 12v power. If you left that alone, and added a circuit to the fuse that has constant power, wouldn't all the new ports operate the same, on all the time unless the switch is turned to off?

I just read all this and was thinking the exact same thing. Flynnster, did you ever give it a try?

 

[dschan]

Reviving a very old thread here, but I'm a bit confused on why this ties into the existing 12v power. If you left that alone, and added a circuit to the fuse that has constant power, wouldn't all the new ports operate the same, on all the time unless the switch is turned to off?

True, he could have left out the diode circuit to the factory outlet. Then the new outlets would be turned on/off only by the rocker switch, regardless of ignition.

But as NH_T4r stated at the beginning, he wanted the option of having the new outlets turn on automatically whenever ignition is on, even with the rocker switch off.

Thanks NH_T4r for the detailed write up with part numbers and pics!