I bought a used ARE fiberglass cap for my 2014 F150. I has a high third brake light that I would like to connect. Doing some on-line searching there seems to be a unused green wire in the wiring harness that supplies power for the third brake light. Various descriptions say it is taped to the wiring harness on the drivers side frame rail any where from next to the spare tire to under the drivers door.
I have done a lot a crawling but am unable to find this elusive wire. Anyone know where it is actually located on my truck?

 

Look at page 4 3rd column over in this link.

https://www.fleet.ford.com/truckbbas...iring_v1-0.pdf

They say the only wire you should use is near the rear bumper/frame area in the trailer tow blunt cut wires.

 

I have given up finding this elusive CHMSL connector and have gone a different route.My F150 has both a 4 pin and 7 pin trailer connector and I only use the 7 pin. I plugged in a 4 pin trailer side connector and ran the leads up behind the left tail light. This gives me left turn, right turn, parking light and ground. I connected the right and left turn to to the cap brake light with diodes in the circuit so the left will not cause the right to flash and vice versa. Connected the ground also and viola. High brake light without cutting into any wiring harness. The light will also flash when I use either turn signal and goes steady when I touch the brake. I understand this may be illegal in some states.

I also ran parking light and ground back down to my rear license plate mounted wireless back-up camera. This lets me turn on the camera by turning on the parking lights. I could easily connect this lead to the back light instead for automatic operation

All the splices are behind the left tail light and all I have to do is pull the 4 pin connector and it is all disconnected.