This is sorta hard to describe, but in my 02 suburban I can't find a comfortable heat selection. I have manual controls, and if you select the blue arc only, it's too cool (according to my wife....fine for me). Just one or two clicks into the bottom of the red arc, and you get so much heat your eyes dry out and you can sweat through your shirt.

It doesn't matter what fan speed you select, but the problem is more pronounced when you select any of the windshield defrost modes. I've even noticed that the plastic around the center windshield vent will warp with the heat...then return to normal when it cools off.

Worth noting that the actual water temp is always running slightly lower than the center or the normal mark. It's not consuming coolant or anything either.

Is this just the design of the system, or is it possible I have a mechanical failure in my HVAC duct-work?