question about the elecrical system?

i want to change my windows from only opening when the key is in the run position to operating in the acc. position, i know its on a timer but if your sittin with the engine off it gets annoying. so if you know some thing i dont, i would be thankful for the help.

 

The power window relay is turned on by the Body Control Module. BCM gets powered up by the ignition switch (turn on signal) from the run position.

 

so in terms of achieving my goal what does this mean? should i get under there with a tester and just start goin at it

 

even if some one could show me the diagrams i could make progress, i do have electrical back ground, just worried about messin up my truck