A/ C not working, or is it?

[mdoyle]

I also have an 03 and noticed the same thing. When I select a temperature and run it on "auto" it cools just fine, but trying to the same thing manually yields hot air.

I wouldn't say it's operating as designed, but the O3's do have a couple of quirks related to programming, (auto-volume and air ride compressor for example) so it's possible that's common.

[mikejr]

There should be a button on the panel that has a snowflake on it, that will power up and power down the a/c. I am trying to recall what the 03 panel looks like. When the line is thru the snowflake it kills the a/c. When you go into auto mode it basically works like your home thermostat and does what it needs to do to keep the cabin temp where you set it. Post up a photo of the panel and i'll tell you which switch to hit.

[working Hummer]

Sounds like everything is running fine. If you push the a/c button several times you'll notice the snowflake go on and off, when the snowflake with line through it is on that turns off compressor. (kind of opposite as you would normally see in other vehicles) If you push auto ,like Mikejr said, it's just like a t-stat and keeps the cabin the temp your set at and will cycle on/off as needed. Hope you now understand the basic use of your Hummer H2 A/C system.

[Devis1957]

It should work in "Manual" mode as well. Check your owner's manual.

[trashguy]

my 03 did the same thing snowflake off had a/c snowflake on had none
my 06 is works normal with the snowflake on go figure?