Not sure of this is normal. No car I ever owned did this. As soon as I start my 2005 H2 the HVAC says auto and blower motor is full blast. Tried disconnecting battery and tried the re learn of actuators. Air doesnt blow cold at all but I think that's another issue. Any thoughts?

 

all depends on the interior and exterior temps at startup,
truck calculates what it needs to do to reach set temps based on sun load, exterior and interior temps then sets HVAC parameters where it wants them to reach desired settings

raise the set temps to something like 80* and then turn the truck off, wait a few minutes and restart, see what the HVAC does.

Neal

 

Aspirator...

 

Well I don't know what an Aspirator is but my 09 H2 in hot weather kicks on the air if I remote start.....Also In winter the heater starts. I believe on the 09 there is a sensor on the driver side tranny tunnel below the shift handle about 1/2 inch in diameter that senses the interior temps. Now if i get in without remote start nothing will be on as far as HVAC goes. Maybe your ambient temp sensor in combination with the BCM is worth checking the schematic on. Just My $.02 Worth

 

The aspirator is a tiny fan assisted thermistor mounted in the lining just above the driver. It connects to the HVAC dash module which uses it to measure the cabin temperature.

If the thermistor goes open circuit you'll find AC goes into max heat mode and fan speed. There is a video on YT

 

Very Cool.... I learned something..