That'* the only one. The only time that sensor is used is in auto. I would still check the air mix actuator to see if it'* moving smoothly.

Thanks!!

That'* great to know.

So if I use my control panel in "Manual" Mode with a particular temperature selected, how does it know to modulate the air mix actuator to maintain the selected cabin temperature if it doesn't use that sensor (near the cigarette lighter)?

My next step is to observe the actuator, then.

Curious. Is the 90 deg setting some kind of a "limp home" mode that drives the actuator manually full hot regardless of the sensor? The air temp got instantly HOT when I selected 90 deg, then cooled off rapidly when I selected 85 deg or any lower temperature. (The actual interior temp was about 60 deg during this test)

I am trying to learn how the digital climate control "thinks" to make its failure more easier to understand.

Bob

The HVAC area is something I'm a little weak on. Wanted to get in to this area but I've been side tracked. I might have mis spoke in my last post. The auto mode turns the blower on and off to maintain the proper temp. As you change the temp setting there is a predetermined set point on the actuator. Watch the arm move. 90* is max temp, so it should move the arm to it'* furthest point.

My own intuition would say that the sensor is used in all modes to tell the air mix to go hot or cold, depending upon whether the cabin temp is colder or hotter than whatever temp is set.

What I don't know is how the air mix actuator knows how far to move. If the cabin temp and set temp are only 2 deg apart, you would't really want full-hot air, but if the cabin were 20 degrees colder than the set temp you might want full hot to warm it up fast.

Hopefully the GM manual will be complete in explaining the nuances of the HVAC system.

To be perfectly honest, I HATE climate control systems, cuz at some point they ALL screw up. Give me a manual rotary or slide control hooked to cables that control the mix flap or hot-water valve and I am a happy camper! Easy to understand, easy to fix.

Bob

I know what you mean. It'* one of the few systems I'm not good with. But there'* always another system that I need to deal with. If it don't make the engine run or make the car go faster, I'm not spending to much time on it.

"If it don't make the engine run or make the car go faster, I'm not spending to much time on it."

With winter coming on, my priorities are changing!

Bob

I hear that. My blower was acting up, so I put a manual over ride switch on just in case the climate control decides to act up again. I just flip the switch and the fan is on full.