Remote control of cargo lights...

[Crf450r420]

I have a wire connecting my reverse lights to the cargo light so they come on when I back up and for a short while when I open the truck at night. Also, because of the wire when the cargo lights are activated the reverse lights come on giving me the most light possible. Now this is great for normal function, but no for actually loading cargo. I have a button to in the bed I just have not had time to run the control wire to the cab (been working on the Camaro and building a friends 900HP blower LS drift motor). Even once this is done, I'd still like remote control of the cargo light and thought I had it figured out. I put a diode between the horn and cargo light control. Now when I honk the horn it controls the cargo lights, but when I double lock the truck and the horn signals it's locked. The cargo lights don't respond. Is there another way the remote activates the horn rather than the X5 BCM plug? I think it's pin 18 or 19, the other is part of the fog lights on with the high beams mod. I'd like to get this working, so if anyone any idea let me know. Thanks.