Ok this is an odd one. I have a 2003 Crew cab with 75000 miles. I have been hearing a weird cliking noise in the back passenger side near the rear window where the defroster electrical connection is located. The click occurs when its warm and cold and has been occurring for around two months now. It almost sounds like a switch is turning on. The sound happens while driving and just sitting running. It also happens when the defroster is on and off. Anybody have any ideas?