Need help with horn causing a stall problem

[dohcter]

Truck is a 2001 with a recent (40k ago) ford reman. It just developed a trouble of stalling when the horn is pressed it stalls the engine. Anyone else run into this trouble? I tired the grounds at the pass fender by the battery, the one on the pass side of the firewall, the one on the drivers side firewall, the two on the drivers side inner fender, and the one on the drivers side kick panel, checked the ground at the engine, and the one from the cab to the frame. Here is a vid. Thanks Psa
http://youtu.be/B3QhcO7KqEc

 

[78f100]

I know this sounds crazy but try a new cam sensor, I had one that would stall every time I turned the blinkers on. Replaced the cam sensor and no more issues.