Having just picked up my truck 2 weeks ago and having only 700 miles on it. I noticed something odd. My seat heaters take a long time to heat up and when they do, I noticed that they only work on the bottom of the seat. In my wife's Pathfinder, they work on the back and the bottom. They also work on the back and the bottom in my 2012 G37. Is it normal for the seat heaters to work only on the bottom in the Titan and should they take 15-20 minutes to warm up?