Help Needed: 12v interior wire on/off with ignition

[wornandtorn]

Hi,

I’m looking for a relatively easy to reach 12v wire in the cabin that powers up and down with the ignition. I need to tap this wire for a footwell lighting project. Thank you for any help you can offer.

Nathan

 

[Malleus]

There is an unused connector under the center console. I can't remember if it's always hot or not. There is also a connector in the driver's side footwell for the front locker that's unused, if you don't have one.

There may be others, but those are the two that come to mind.

 

[Broski]

If you have your rear heater deleted there’s a 20 amp switched connector under the passenger seat

 

[robnicko]

Cig lighter wiring

 

[wornandtorn]

Thank you guys very much! That’s a good list to work with!

 

[NTH89]

If this is for your footwell, I’d do a fuse tap right there to the left of steering wheel.

 

[Broski]

If this is for your footwell, I’d do a fuse tap right there to the left of steering wheel.

I would use a fuse tap as last ditch resort
JMHO

 

[western flyer]

2X above recommendation by robnicko. I used the cig lighter circuit when I needed switched power with IGN near the dash. Also works on ACC IIRC.

 

[BucketEighty]

I pulled the interior fuse box out a little (to access the wires) and wire tapped the power-in side of the cigarette lighter fuse. I put in an inline 5V fuse after the wire tap (for safety) and sent that wire to my auxiliary fuse block to use as a signal for a big relay that turns on a bank of fuses that I want to be hot only when the ignition is on. Probably more hassle than you're interested in, but it's nice for future mods to have a bank of available fuses that are always on and a bank that are on with the ignition.

 

[GeoRoss]

The old factory amp too.

 

[Malleus]

I would use a fuse tap as last ditch resort
JMHO

I would never, ever tap a wire. It's too eay to do it the right way.

 

[BucketEighty]

I would never, ever tap a wire. It's too eay to do it the right way.

I’m not an automotive electrical person, just a DIY person. What’s the right way? Are wire taps not reliable? This project is the first time I’ve used them and they sure are easy and have nice built in insulation and strain relief compared to some crappy solder joints wrapped in electrical tape I’ve made in the past.

Please share how and where you’ve had problems with wire taps so I can decide whether it’s worth tearing my dash apart again to remove and redo the couple I installed. I used some to tie power and ground together for my dash fog lamp switches too since they seemed easier than crimp connectors for making that harness.

 

[Malleus]

The correct way to "tap" into a connector housing is to remove the terminal attached to the wire you want to "tap" into, place the OEM wire and your new one in a new terminal and reinsert that into the connector housing. Having said that, tapping into the wiring harness is a generally bad idea, unless you've taken the time to analyze the circuit and are 100% sure you haven't exceed the circuit load. There may be 3 people in the world who do this.

That's why it's a much better practice to use unused connectors which are already in the wiring harness; they're already fused and not currently sustaining any loads. You can buy the mating connector housing, a terminal or two, and make a pigtail you can install and remove as you please.

My problem with vampire taps is that they break the insulation and the stranded conductors in the harness, leaving you with:
a) an exposed wire that attracts corrosion and is a failure waiting to happen, and
b) breaking 20 ga stranded wire means you now no longer have 20 ga wire in that circuit; it's less by however many strands are remaining in the conductor. And there aren't that many strands to spare in a 20 ga conductor.

IMHO, these things are made for people who work on other people's cars and can afford not to worry about electrical failures - because it won't happen to them.

We really need a stump dismount emoji...

 

[landcrshr]

The correct way to "tap" into a connector housing is to remove the terminal attached to the wire you want to "tap" into, place the OEM wire and your new one in a new terminal and reinsert that into the connector housing. Having said that, tapping into the wiring harness is a generally bad idea, unless you've taken the time to analyze the circuit and are 100% sure you haven't exceed the circuit load. There may be 3 people in the world who do this.

That's why it's a much better practice to use unused connectors which are already in the wiring harness; they're already fused and not currently sustaining any loads. You can buy the mating connector housing, a terminal or two, and make a pigtail you can install and remove as you please.

My problem with vampire taps is that they break the insulation and the stranded conductors in the harness, leaving you with:
a) an exposed wire that attracts corrosion and is a failure waiting to happen, and
b) breaking 20 ga stranded wire means you now no longer have 20 ga wire in that circuit; it's less by however many strands are remaining in the conductor. And there aren't that many strands to spare in a 20 ga conductor.

IMHO, these things are made for people who work on other people's cars and can afford not to worry about electrical failures - because it won't happen to them.

We really need a stump dismount emoji...

He was talking about a Fuse Tap, not a vampire tap, which is slightly less jankey.

https://www.autozone.com/electrical-and-lighting/fuse-and-accessories/p/bussmann-atm-fuse-tap/32416_0_0