Full Time 12V Power Outlet rewire for '04 Corolla

Unplug the wires from the back of the sockets, install some shielded connectors on 12 gauge wire to plug into the back of the sockets, and tap the fused side of the dome fuse with a tap connector made for the purpose.

Easiest and safest way is to add an auxiliary power socket and leave the factory lighter socket power supply alone, since it has a thermal protector in it that you can easily trip by running power accessories for long periods. Plus, having the lighter socket power switched is a safety measure to keep from lighting the car on fore - it's fairly easy to drop a parcel or item and push in the lighter element to where it won't pop out and shut itself off.

Add an auxiliary power outlet under the dashboard. If you only need

5 amps or so, tap off the dome light fuse (or another constant circuit) at the fusebox - they have "Add-a-Circuit" taps that plug into the fuse holder prongs and give you a second lead.

How much power do you need for these accessories, and for how long? (So I can come up with an average amp-hour draw.)

You can't use a lot of power (I'd stop at 5 Amp-hours) with the engine turned off without deep-cycling and ruining the regular starting battery - they do NOT like that usage, they are made to give a big burst starting the engine and then be immediately recharged.

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No lighter element came with the car, just the cigarette jack and a plastic cover. The label inside the cover sais "don't exceed 50W". 50w/12v= 4.1Amps. I'm way under that. So I'm not worried about fire or anything dropping in it. I only plan to use a GPS unit. 300ma. I prefer using the cigarette power jack. Perhaps I can jumper it to the "Add-a-Circuit" tap. I don't know where the cigarette power jack wire ends up; in the fuse box or somewhere else ?

The cigarette power jack wire ends up at the lighter fuse.

But you can see how wedging the lighter element in can cause it to get way hot, right? When you do the dodge below, hide the element so someone can't play with it...

But after that (feeding the fuse) it goes through the accessory relay in one of the fuse blocks, probably the one under the hood.

You can use an Add-A-Fuse tap and wire one in reverse - Tap off a constant fuse (like the Dome light) to get the always on lead, then connect a .110 male tab crimp connector to mimic a fuse prong and plug it into the "out" side of the Lighter fuse to feed constant power to the lighter. Easily reversible when you sell the car.

If that makes no sense, print this out and go find a radio installer or a mechanic - they'll go "Oh, Yeah!" and fix you up fast.

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Thanks all.

The radio is on the same 15A fuse as the 12V accessory for some reason. I don't want the radio on all the time though. Any idea where the radio and accessory wires are joined ? in line somewhere or at the fusebox ?

Thanks J

I can't answer your question without a wiring diagram, but you can get taps for blade-type fuses and insulated crimp connectors for the taps at auto parts stores. Tap the fused side (the side that gets disconnected when the fuse is pulled or blown) of a fuse that is always hot, like the dome light; connect a female insulated blade-type crimp connector to a wire and connect the wire to the accessory socket. Look at the back of the socket for a connector that will fit, and unplug the factory connector. This way, you do not disturb the factory wire harness and can easily return it to factory condition when you sell the car.

If you are plugging in small things like a cell-phone charger, go get an Accessory Power Socket to mount under the dashboard, a small spool of #14 wire, an inline ATO fuse holder with a little plastic flip cover for the fuse, a 10A ATO Fuse, and an "Add-A-Tap" adapter. A few barrel crimp connectors and a pair of electrical stripper crimper pliers.

Oh, and get an ATO "Spare Fuse Kit", so you have an assortment of extras with you at 2AM, throw it in the glove box. Use an ATO inline fuse holder, for the simple reason that you only need one kind of spare fuses to match what the car uses. No box of spare 3AG glass fuses to add to the clutter.

Mount the socket somewhere knees and legs won't be hitting it. If the dashboard isn't grounded steel in that location, hook a wire to the baseplate and go to the main body ground bolt, usually in one of the cowl panels in front of the doors - where your outboard ankle is when seated.

Run the lead from the +12V center tab of the accessory socket over to the fuse box, tying it up out of the way of sharp edges and moving parts (like the brake pedal linkage) with nylon wire ties.

Splice the power lead to the in-line fuse holder, and splice the other end of the fuse holder to the Add-A-Tap. With a test lamp (looks like an icepick with a ground wire on the handle) find a fuse that's constant on, like the dome light. Remove the fuse and figure out which end is the power in, and put the end of the Add-A-Tap with the tap wire on that end. Replace the Dome fuse in the fuse socket part of the Add-A-Tap.

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(And remember NEVER GO BIGGER than the fuse holder markings, if you plug in the fuse and it pops immediately there is a problem that must be fixed. Try to stick a 30A fuse in a 10A slot "to get home" and you could start a nice electrical fire and totally destroy the vehicle. $3,000 worth of damage usually totals out most cars.)