Maybe try to install toggle or push buttons in line to those two wires so that by switching them on in a certain order, you can fool the system into thinking you have parked and are
setting the parking brake! My guess to the order would be as follows, for most units I
have seen or installed:
* Push brake pedal;
* Set parking brake within (X) seconds, or before releasing brake pedal;
* Release brake pedal to activate screen/system, etc., for viewing.
This is done on a two wire safety/trigger as you have said that you have.
Bypass and directions;
* Connect the +/brake wire to a momentary push button switch (normally off, or open
circuit type), and then to a positive wire from truck;
* Connect the -/e-brake wire to the toggle switch, as this has to mimic the parking
brake remaining on the entire time (don't want a momentary switch for this one!).
can hook other terminal of toggle to negative wire or frame ground.
"Fool the Computer Mode";
* Push momentary switch/button and hold while;
* Flipping toggle switch to the on (grounded) position;
* Release momentary button (positive signal).
Computer thinks you hav hit the brake pedal, set the parking brake, released the
brake pedal, and are safely parked.
Oh, and I hope you didn't have to hook up a VSS (vehicle speed sensor wire),
as that would throw this whole plan out the window! As it senses an input, and overrides
my previous suggestion. Haven't seen one of these yet, but I've heard that they are out
there. If you do find that yours has the VSS interface, let me know, and i have a way to
trick that little sensor into behaving, as well! But for now I will not make this post
any longer!