In the 15-18 F150 and 16-18 Exploder it’s BCM line 726-37-01, but that doesn’t correspond with our trucks.
726-15-01 is the door keypad enable/disable; -16-01 is Smart Unlock; and -19-01 is Remote Start.
That being said, you are moving into uncharted territory across the model lines for our particular coding.
I’d look at changing 726-17-01 and 726-18-01 to see what effect it has.
-17-01 should be 0101, so try changing it to 0001 and 0100 and seeing if there is any effect. I’m thinking it’s possible one is the horn and one is the lights.
If not, move on to -18-01. It should be 0100 0000, and you could try changing it to 0000 0000 and seeing if that works. If not, I’ll dig down into the later lines of code and seeing what else could be it.