tobnpr

Just purchased an '08 Trailblazer, and the owner's manual states that when the defrost mode is selected for the windshield that the a/c compressor automatically kicks on when the outside air is above 40 degrees.
(Dual climate control system).
This is a huge problem. Here in FL, we have 100% humidity and temps near 80 degrees in the summer before the sun comes up. Having a windshield cooler than the outside air, precipitates fog on the outside of the glass resulting in a windshield you literally can't see through. I crank both temp ***** to 90 degrees but air coming through the vents is still cooler than the outside air. I need HOT air on the windshield to warm it- not cool it. Currently I need to open all the windows and sit for 10-15 minutes so the windshield glass temperature equalizes and the fog on the outside of it no longer forms.

Is there a way to override the a/c compressor kicking on whenever the defrost mode is used? This is a HUGE problem and design issue IMO.
Thanks in advance for any suggestions.

jfmorris

I see the issue you are dealing with. My truck has manual AC controls, so I can run the blower in the defrost (windshield) position with the AC compressor turned off.

That said, I tend to be hot natured, and crank the AC most of the year. It's very humid and hot much of the time here in Alabama as well. If my windshield fogs up in summer on the outside (and it does), I turn on my windshield wipers on a slow interval to wipe the fog away, and proceed with my driving. I sure wouldn't sit for 10-15 minutes. Fog on the inside would be a different story, but fog on the outside - can't your wipers take care of it?