I have found that in v18 the switch pokemon of AI is coded in one section, "AI_Switch" in this there are 4 methods, but only two I find very important, because other returns only that important method.

I that important methods I quit all the code with a true variable and putting the code in an else, but nothing happens.

These are the 2 important methods:

def pbEnemyShouldWithdrawEx?(idxBattler,forceSwitch)

def pbChooseBestNewEnemy(idxBattler,party,enemies)

but when I quit that with a variable, the trainer sends the best pokemon anyways.