Tapping 12v power for bed - with ignition vs always on

Planning to install a 12v socket in my bed for various accessories but want it to be powered with ignition rather than constant on.

Is the black wire in the 7pin towing connector always on or only comes on with ignition? other ideas?

any taillight wires?

worst case I would run an add a fuse from the cab and run a wire all the way back to the socket but would prefer to keep the wiring local. will wire in a 15amp fuse as well.

 

The black wire is for the brakes.

The blue wire is battery charge/power. It’s operated off a relay. Which looks to be controlled by the ignition. A test light would confirm this.

Or ask @caribe makaira he probably already answered same question at some point. And may know a better place to tap from

 

I have a volt meter, USB and 12V outlet back in my bed, I have it wired "always hot" with fuses at the blue sea fuse box behind my battery in the engine bay and just have a switch at the accessories so there's no current when the toggle is off though the wires are hot.

IMHO a much better and simpler solution than trying to have something only on with the ignition.

The added benefit I can charge my phone or check my voltage without even having the keys on my.

I charge my phone, camera, and, run a small blower fan while sleeping back there and the voltage only drops .2v max over night doing so.

Running a 27F X2 Power AGM FWIW.

I like this set up as I can have power without worries of sleeping in the back with the truck unlocked and the key in the ignition, plus it isolates and other OE accessories parasitic draw as you would have with the ignition in ACC but engine off.


So I guess what I'm getting at is why do you want it only hot when key is on?

 

Blue is brake controller output. Black is constant 12v to charge trailer battery. No ignition that I know of in the rear. I’d run a dedicated power line. That’s my plan at least. High current relay works for max power but they need waterproofing. Easiest option is a switched power distribution with 12v fused feed. Then you can turn it off independent of ignition.

 

Yeah, what @Key-Rei said.

 

I am wanting to run a rear facing dash cam so want it on with ignition. I have a good camping battery pack for when sleeping in the bed on other occasions.

Sounds like the blue wire may work. I will check with a multimeter. plan is to wire an in-line fuse as well to that wire running off the tap.

 

I have an A129 Duo (front and back cam) I run 100% of the time, it's also switched but I just leave it on full time as a security cam if you will, had one of those "wake and record on motion" cams but it was either way to sensitive and would record if the wind blew on the truck or not sensitive at all and either way any footage I got from it was always too late to be useful.

FWIW I can go 4 days with my dash cam recording full time before I need to start the truck and or charge the battery up with my plug in box.

 

hmmmm yea I could consider a 2 channel. where did you run the cable to the bed? I have a shell so would need to run it to the back window of the shell. That is one of my possible COAs

I do already have a pop and lock installed so I have a cable running through the rubber under the drivers seat so could just double that up. assuming the cable is long enough.

 

Oh I’m wrong on colors? They are blue and black in the cab though. My bad. Oops.

 

Same it's stuck to the back window, I have a dummy long mini usb cable specifically for dash cams goes from the cam on the left side of the rear topper window (have a tire carrier bumper with a 34" tire blocking it's view from center and right side) along the top of the hinge to the right side down to a grommet or gap in the bed I forget which, then it runs along the big power supply wire for my previously mentioned rear accessories and air compressor which runs along the factory wiring harness on that side of the frame just zip tied at the factory spots and wherever I felt necessary where it merges from that loom up into the rear cab wall right side about 1' up where I popped out a factory plug grommet and used a pass through grommet into the cab through the back wall sealed with Toyota FIPG-103 (some people run them through the pressure equalisation shutter vents if you have a 3rd gen or double cab there's one on each cab side access cab 2nd gen at least only has one and it's high up in the middle of the rear bulkhead) then along the door trim wire looms up the the A pillar then up that behind the trim and to the dash cam front and center of the windshield.

 

i can confirm that the trailer plug positive is controlled by a relay-- it's a sidecar relay to the main fusebox under the hood.

functionality of the relay would depend on vehicle programming, so i can't confirm if it comes on with acc, or only when the engine is running, or other oddball middling scenarios.

but i can confirm that opening up the relay and slipping a ziptie in the magnetic gap will lock the relay on!

 

Just checked actually with a meter and seems like the + connection on the 7pin is tied to ignition I tested with truck off and running and only drew power with truck on so I may be in business just tapping the + wire as per the diagram on the pin cover

 

According to quick test with multimeter, pin # 3 as per makaira's image is tied to ignition and not always hot

 

Funny cause I coulda sworn caribe was the source of my Intel on battery vs ignition. I guess always good to test.

I would still run my own circuit though. That’s just me.

 

A 10awg wire with male terminals as a jumper would do "better"...

 

Thanks Caribe

 

i did consider it. i've got the #10 wire and the terminals. then i saw that it's got a 40A fuse going to the relay. i know the relay is rated for 40A from the factory because the factory put it there, but i really need #8 and matching crimps i don't have to do it that way.

and this way i keep the relay in the proper location which is less stuff to lose. if i ever need to tow i can easily revert it back with parts on the truck, on the side of any road, instead of relying on my terrible memory for where i put the 'old' relay.