I'm sure it's already been addressed in a post somewhere so if you know the thread point me in the right direction plz. If not I'm at wits end. I've got the pdf repair manual. Unfortunately the wiring diagrams leave something to be desired. I've replaced the brake switch, tried bypassing pk/db (power in), tried direct wiring bulb to battery (just get sparks). All my other lights work - taillights, blinkers, back up and hazards. No burned out bulbs. None of the 3 brake lights work. I know the wt/br is power out to brake lights from switch (top middle cab light). Not sure when or where it switches to bk/to. Any ideas would be greatly appreciated.