I bought my new F150 about a month ago.
2019 F150 XLT 4 door 2.7eb 5.5 bed. We are still getting to know each other.
The dealer added some custom stuff, leveled it, big rims and tires, leather interior, etc.

It is a work truck and I have a back flip bed cover on the bed.
It seems solid, but to me it looks kind of vulnerable, where it meets the tailgate. It seems like I can slip a pry bar in there and pop it open. It is nagging me in the back of my head.
I added these 2 limit switches to the bed so they can sense when the bak flip is open. I want to tie them into the existing security system. I assumed that I could just tie into a door switch. UHOH, there are no door switches! There is some kind of door ajar switch built into the latch in the door.

My truck has some kind of factory security system. If I lock the truck with the windows down, then I reach in and open a door, then the horn goes off and I get a notification on my phone. Perfect! How can I tie my limit switches into this system? I tried to get a door panel off, and I couldn't. It's still a new truck and I don't know what I'm doing when it comes to interior panels and stuff. So I stopped before I broke something. I am very strong electrically, so I went probing wires in the rr door frame under the plastic. No joy. I tried the drivers door. Still no joy.

Does anyone have a wiring diagram or schematic for a 2019 F150? Or does anyone know which wires I should be looking for?
I think the door ajar actuator switches ground to something, but I'm not sure.
Or maybe just trigger the dome light? I'm not sure if that will activate the alarm but I can find out easy enough.

any help or guidance will be greatly appreciated.
Thanks in advance.

 

Do some searching... there is a "tailgate ajar" circuit that you can use. It's been discussed previously. Use a magnetic switch, tie in there, and you'll get alarm if someone crowbars in plus an ajar indication if the tonneau comes open.

 

tailgate ajar
thank you for that
I went right to it
I don't even have to run wires to the cab. Perfect!

 

Man that was way harder than it should have been. But I'm done and it works.
I watched the video Right at the 2 minute mark he gets into the connector at the BCM. No yellow/Orange wire in pin 34. Freeze frame at 2:16.
Thats why when I grounded my wire nothing happened.
I am very impatient and I did not want to order the little female connectors so I jammed a wire down that hole and secured it with a wire tie. I drilled a tiny hole through a white nylon hole plug under the front passenger door trim, the plastic part that pops off. I ran my wire from the blue connector, through the nylon fitting and out. Then I ran my wire inside the passenger side frame rail to the end of the truck. I made my connections and it works!
Thank you to everybody for all your research and help. I would have never found this without you. Especially Chad Fraser, the guy who made the video.
pin 34 in CPL 44 Jheez.