This is on a 2005 F-150 Lariat so it could be different for different model years. I looked on the forums for 2 days to nail down the location of this wire. I saw different posts some saying the wire was green, others saying it was black and pink. All posts agreed it was in the kick panel but they could not agree if it was on the passenger side or driver side.

I finally found my wire which when your truck is reverse and the key is on, becomes hot and will activate a reverse/backup camera and or the backup feature on your double din head units.

Mine was located on the drivers side kick panel. There is a grey connector secured with a bolt through the center. If you look towards the back of the connector (towards the firewall) you will fine a black wire with a pink... almost purple stripe. I probed the wire and determined it only becomes hot when the truck is in reverse and the ignition is on. I tapped into the wire, and then taped it off.

I took a few photos in hopes that I could spare someone else the trouble of probing a ton of wires "I must of probed 10 different wires combined". Hope this helps someone.

 

The truck's reverse circuit is black w/ pink stripe wire at the rear of the truck, and it changes to Dark Green w/ Yellow stripe wire at connector C405. In the driver's side kick panel the Dark Green w/ Yellow stripe wire splits off to the Park Aid module and to the electrochromatic mirror and back towards the source at the DTR ( Digital Transmission Range ) Sensor.

Both kick panels is the correct answer for the black w/ pinks stripe wire.

The wire you found is the output of the trailer tow adapter reverse circuit, after the trailer tow reversing lamp relay in the fuse panel on the passenger side.

This is why both the passenger and the driver's side is the correct answer for the trailer tow adapter reversing circuit that you are using in this case.
It is not wrong to use this, just be aware that if for some reason you pull the trailer tow reversing relay or fuse #10, the circuit you are using will be dead, and the truck's reverse lamps will still work.

 

Well I guess that solves it!. I tried the passenger side first and could not locate the black and pink wire but either way this should help people. Thanks for the info. I do not plan on ever pulling the fuse so I should be good to go.

 

Just wanted to clarify the confusion on the where.
By the fuse panel is not the easiest of places to find things.
To add insult to injury, the Dark green w/ yellow stripe wire is in connector C270B and the output of the trailer tow reversing relay is in connector C270E.
The circuit supplying power to the DTR is a Light Blue w/ pink stripe wire, also in C270B.

Also just looked at an electronic copy of the reverse lamps diagram, and it shows the trailer tow reversing relay as non serviceable ( i.e. soldered into the fuse panel ).
So remove that from the "what if" list above, it is now just the fuse.

- There is a bit of contradiction from electronic to print at time, depending on the revision of the print copy.

** I'm going to send off a PM to have this moved to the technical articles sub forum, they will clean up my BS'ing posts when they move it.

 

Ok, so I may have to edit my initial post because the saga continues.

I got my head unit in today the AVH-P4400BH. Got it all hooked up and everything worked great including the reverse camera. However later in the day the reverse camera stuck on and I had to pull the battery cable to reset the unit to remedy it. But when I shifted into reverse the camera no longer worked. This solely rests on me for not using a volt meter but being lazy and just using a probe. I ran a jump wire from a 12v constant and tested it and saw that it would trigger the reverse camera. I again probed the wire I had ran from the above post and noticed that even in reverse it was lighting the probe "slightly have to really look to see it" So I pulled that wire and tested it and saw that when I connected it even when not in reverse it would trigger the camera and when I disconnected it, it would revert back to the main screen like it should. I am not sure why I have phantom power on this line and I do not have a volt meter to measure "will tomorrow" but I have a theory. The camera wire has an additional acc connection. I am wondering, I tapped into the reverse trailer circuit in the rear for my main power. I am wondering if somehow I am getting feed back through the camera back into the main line in which case I need an diode to stop this. Worst case scenario I am just going to run a new wire from a reverse light up into the cab. Tomorrow will tell once I get a volt meter on these wires and figure out what exactly is going on. Just though I would update this as I went.

 

The picture shows what looks to me to be a Black w/ violet stripe wire, not black w/ pink stripe.

You posted it was pink, but almost purple stripe wire.

Might want to go back looking, as the pink stripe wires in the close up look pink where what you are connected to looks to be a violet stripe wire.

Just got a moment to pull up the EVTM for the 2005 MY, to get the connector face view.

This is it, one side is a close up of the pin you need for the trailer tow circuit


The connector is mounted upside down in the truck, pin #42 is a 12 AWG red wire. This picture shows it is center bottom in the mounted connector.



Circuit #53 for the interior lamps is pin #6, and in the bottom picture is what the cleoid is hooked on ( towards the top of the mounted connector ).

The trailer tow reverse lamps should be 7 pins lower than circuit #53 on the side of the connector against the a side of the truck ( about where the knurling is on the cleoid ).

Hard to tell where you got that black w/ violet stripe looking wire from, could be in the same area.

The connector face includes a few wires around pin #13 to try to help locate it.

 

Okay, got it figured out... Don't ask why I didn't put two and two together, but this problem started after I washed my truck in the laser wash... come to find out some water got into the four pin connector in the rear and was causing a small bleed across. All is fixed now, everything sealed up tight, shouldn't be an issue any longer. Thanks for all the help. Really appreciate it.

 

The flat 4 trailer tow adapter does not have reverse in it, only L & R Stop / Turn, parking lamps and ground....

 

Sorry I meant the 7pin, I left the cap open on it "springs broke". I was thinking about the 4 pin when I was typing and my dyslexic brain let me type it. I'm just glad it works now.