Electric Brake Controller

[Yendor]

So can anyone see a major problem with picking up the brake switch from the trailer plug itself?
The wire to the switch on the pedal has no play in it for me to splice in and solder. I was thinking of running a two core cable to the trailer plug, one to pick up the brake switch circuit, the other to activate the brakes on the trailer.
Thoughts?

That's no problem at all. In fact on modern vehicle's that's standard procedure. You can actually purchase aftermarket wire harness to suit.

Such as this http://www.autoairparts.com.au/wp-co...rake-Cable.pdf