HVAC

smoke · November 8, 2006

I have an '06 Sierra crew. I want to know if the vent system 'defaults' to the recirculation mode when the truck is turned off? Now that it is getting cool here in FL, I am just using the outside air through the vents. I have to briefly activate the AC system to get the air from outside rather than inside. Sounds weird but I want to know if the solenoid closes and when you think you are getting outside fresh air, you are really getting recirculated interior air?

Thanks.

GD

GM-Tech · November 8, 2006

If the a/c system is off, you should be getting outside air, not recirc. air.

smoke · November 9, 2006

SCENARIO:

A/C is on with both the A/C button and recirc buttons activated (Lit Yellow), the air is being recirculated. I now, press both buttons to deactivate.

Does the solenoid automatically change from recirc to outside air? I think the routing stays in the recirc mode.

Thank you.

GD

GM-Tech · November 9, 2006

Does the solenoid automatically change from recirc to outside air? I think the routing stays in the recirc mode.

what makes you think that?

smoke · November 9, 2006

I only think that because what would physically change the ducting from recirc to outside? The other day here in FL it was 70ish and sunny. My windows were closed and the interior was very warm. I tried a test by just using the fan. It blew warm air. Even taking into consideration the heating of the dashboard, the cooler outside air should have started to enter the cab. It did not. I activated the A/C button and I heard the whirring under the dash. I killed the A/C and after the brief conditioned air, the more cooler exterior air began to come out of the vents.

Hope this was clear.

GD

asilverblazer · November 9, 2006

It probably is working, keep in mind the dash isn't the only thing warm, all the duct work is too. 70 degree air will not air cool all the items, between the cowl and your face very quickly. When you turned on the A/C that air was much cooler and capable of cooling the ducts and air. Then when you flip the A/C off the outside air is blowing across cold surfaces from running the A/C so it will remain cooler longer. Also 70 degree air blowing on your face in a hot car is not very cool feeling. The noise you heard were the A/C going to "MAX" setting (Recirc. and A/C buttons pressed). Plus I don't think the switch between Recirc. and fresh air is audible, in my truck.

P.S. My experience is there isn't much difference between recirculate mode and fresh mode except fresh mode let's dead skunk stink in faster.