as per other thread. for pre 2005 SR5 hilux's.
disconnect that sensor. that sensor there appears to short out the 4wd circuit when you flick the gear stick into low range.
so once that is disconnected, you can shift from high range to low range in 2wd with the option of pressing the 4wd button on the short gear stick to lock it into 4wd in either high range or low range