Bought this truck used a couple months ago. I basically have three seperate but I suspect related problems. 1: Headlights flashing or coming on when switch is in parking light position. 2:Wipers when on delay sometimes double or triple wipe. or swipe once when switch is off. 3:No power to trailer brakes when pedal in truck is applied. Power is there when brake controller is operated manually. I suspect a PDM or FCM problem is causing all three problems. Any reliable fixes without throwing parts at it?? Can the corrosion problem be fixed by cleaning terminals?

 

There are many wiper problem posts. Mine do the same thing, I just read on this site that replacing the wiper motor is a solution. I have read other places pushing your wiper relays in harder helped, testing relays, replacing multi function switch (wiper switch on steering column). I have had a new fuse box installed and it helped a bunch of electrical problems. I think my pdm was replaced if that is something different. Was under warranty at dealership.