When I turn off the AC button, and then turn on the recirculate button only, the AC compressor come on.... (?)

 

Recirculate ONLY works with AC. Read your owner's manual.

Note where it says: "When the recirculation mode is turned on, the air conditioning will turn on automatically."

 

Same with the defroster

"(Defrost): This mode directs most of the air to the windshield, and the side window outlets. When this mode is selected, the system runs the air conditioning system unless the outside temperature is near or below freezing."

 

Wow, you mean that the owner's manual actually has information in it about the H3? Whoduthunk?😜

 

Just in case you don't have the owner's manual:

https://schwarttzy.com/h3-hummer/#h3-hummer-manual

 

I bought this H3 new. 2008 5IL.

It just hit 8,500 and the ECM went out, about 7 months ago while driving down the road out of town. As the ECM was going out my odometer started rolling like a slot machine.
When it finally stopped spinning, it landed on 95,000. Long story short, in went in one side of the GM dealership and came out the other-side with 98,500.
So basically my car screwed me out of around 11,000 miles.

All that said, I know for a fact my AC compressor never engaged with just the recyclable on and the AC button itself off.
Whenever it got to cool in the car I would turn off the AC button and leave the recycle on, the compressor stayed off.

If the compressor did engage, this is the first time since owning my H3 that I've been able to notice the recycle button engaging the compressor since replacing the ECM.
The reason I posted the question!

I would like to thank those that actually took the time to answer in a mature manner!

 

When the recirculate is ON, the compressor goes ON in order to remove humidity from inside the cabin so it doesnt build up on the windshield/ side windows.

 

Thank You! I guess my H is getting to the age were I can feel/notice things I’ve not noticed in the past.