Hi,
In the cooler evenings I like to open the windows and have the fresh air fan blowing air from the dash vents. In my 03 Expy it will blow hot air that it must be picking up from the engine compartment. I tried to turn on the AC on to cool the vents tubing down but it just turns to hot again after the AC is off. You can usually hear a thump it you turn to MAX AC so I assume that is the blend door working.
Are others experiencing the same hot air or do you get cool outside air?
Do you think I have a problem?
Thanks,
Gary

 

my vents always blow warm... but not hot. I've never tried it in the winter when it's really cold outside. I just assumed it's the routing of the air ducts that heats the outside air up. I have the climate control thing in mine and if it's not actually heating the air then the a/c seems to be on, there's no middle ground, you either get heat or a/c. So I guess I'd say yeah, I'm experiencing the same thing as you.

 

Double check your owners manual if you have ETC (Electronic Temperature Control). My '02 Navi manual states that the A/C will not engage if the mode is set to 'vent' or 'floor'. (My wife's Sable manual states that the A/C will not engage if the mode is set to 'Panel'.)

 

yeah, I should have clarified that. In vent mode it's outside air, but it's always either warm or hot. In the 'auto' mode, it's either hot (heated air) or a/c.

 

Thanks for the feedback. I guess it is just the way the venting is routed. I guess I just have to use the AC more than I would like to.

 

Nope, the thump is the outside air vent being closed. Outside fresh air is always drawn in except on max A/C. In that position the outside air door is closed so that the air is recirculated from within the cabin. Since the A/C system is cooling cooler and cooler air the longer it runs, it helps the whole system work better on very hot days.

That being said, your blend door might not be going all the way over to the cool side and is allowing heated air to come in from the heater core. BTW, the fresh air intake is that grill right in front of your wiper arms. With the hood closed, it is unlikely that you're getting heated air from the engine compartment drawn into it.

 

Thanks. Very useful info. I am going to check the blend door operation to make sure it is working correctly.

 

I just noticed the same thing on mine today. Time to search "blend door".