Heat / AC / Climate Control

CXRabbit

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2009 CX-9 TR +Kenwood DNX7020EX
I have questions :)

(yes, tomorrow while I wait for the remote start to be installed I'll be reviewing the owner's manual again.)

GT with Climate Control.
I haven't been using the "auto" feature much because everytime I do it wants to pick the vents and turn on AC. Admittedly, it's been warm here - like 60 (cold air coming in tonight) so I can't tell if it's functioning correctly or not. I'm also not crazy about the fact that when you have it in "auto" mode you can't change anything without it coming out of auto mode. For example, I hit auto and it selects the dash vents. I want it on feet and windshield but the minute I hit "mode" it's no longer in auto mode. Climate controls I've seen in other vehicles allow some modification but are still in "auto". I also don't want the AC running all the time and so far whenever I've hit "auto" that's what happens. This cannot be good for gas mileage, and it's especially unnecessary in 50-60 degree weather.

I have reviewed the owner's manual and it seems that once you hit "auto" there's nothing you can change without ending up in manual mode. Does everyone agrees?

What am I missing here? Anyone driving in cold weather yet notice if AC still stays on when in Auto mode? Anyone know, is it REALLY turning on the AC? Anyone compare impact on Gas Mileage with and without "Auto"?

Fill me in if you can...
 
CXRabbit said:
I have questions :)

(yes, tomorrow while I wait for the remote start to be installed I'll be reviewing the owner's manual again.)

GT with Climate Control.
I haven't been using the "auto" feature much because everytime I do it wants to pick the vents and turn on AC. Admittedly, it's been warm here - like 60 (cold air coming in tonight) so I can't tell if it's functioning correctly or not. I'm also not crazy about the fact that when you have it in "auto" mode you can't change anything without it coming out of auto mode. For example, I hit auto and it selects the dash vents. I want it on feet and windshield but the minute I hit "mode" it's no longer in auto mode. Climate controls I've seen in other vehicles allow some modification but are still in "auto". I also don't want the AC running all the time and so far whenever I've hit "auto" that's what happens. This cannot be good for gas mileage, and it's especially unnecessary in 50-60 degree weather.

I have reviewed the owner's manual and it seems that once you hit "auto" there's nothing you can change without ending up in manual mode. Does everyone agrees?

What am I missing here? Anyone driving in cold weather yet notice if AC still stays on when in Auto mode? Anyone know, is it REALLY turning on the AC? Anyone compare impact on Gas Mileage with and without "Auto"?

Fill me in if you can...

It isn't explained very well in the manual, but here's what I've pieced together from the manual, quickstart guide, and observation.

1. When you hit AUTO, it chooses everything, and will choose which vents to use based on ambient air temp and the temp you've requested. Mostly, here it seems to like defroster and floor vents, but on occasion (warmish day), it would choose face or face/floor.

2. The manual states that just because the A/C green light is on, doesn't mean that the AC is actually running. I think it's just to let you know that it's a possiblility. I have felt the AC kick in an out. If it's a cool day and you push the A/C button, turning off the green A/C light, the system will still try to keep the cabin warm; you just lose the ability to defog the windows until you go full-auto.

3. The manual also states that when you select the defrost vents, the AC is turned on; this is the defog mode. Haven't verified yet, but I think the system "sees" that it's cold out and selects the defog mode when you first start up. On a longer trip, I saw it switch from defrost vents to the face/floor combo. By that time, though, it had warmed up outside and I actually needed the AC. Or maybe it just switched because I needed the AC.

4. You can go AUTO and select whatever vent you want. The green AUTO light will go out, but the system will still control the temp.

In short, there seems to be three modes: AUTO, semi-auto, and OFF. It bothers me a bit to see the A/C light on when it's 30 outside, but I think that most of the time, when ambient is below the selected temp, the compressor isn't running. On the trip mentioned, I had the cruise set a 77 and rolled on the Interstate in fairly light traffic for six hours. I got 19.8, 20.3, and 21.0 mpg, which fits with the idea that the system really was turning off and on the compressor as needed.
 
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Thanks for all the info... I didn't get a chance to read the manual today because it was an adventure at the audio place (for another post)... so I appreciate what you wrote.

Also, from what I've read, it also seems that whenever you select foot, windshield/foot or just windshield the AC is automatically turned on, even if the AC light isn't on. That seems inherent to all Mazdas (a guy on the Mazda 3 forum was actually pretty mad about it). I don't mind any of this as long as it's not a huge hit on performance/MPG.

Notice any differences with auto on/off?
 
CXRabbit said:
Thanks for all the info... I don't mind any of this as long as it's not a huge hit on performance/MPG.

Notice any differences with auto on/off?

You're welcome, but take it with a grain of salt--any or most of it could be wrong.

The only way to really find out when the compressor is on is to have someone watch it while shifting modes. I really don't think it would be on for foot-only, but foot/windshield or windshield only I'm pretty sure it is on, or at least enabled. Again, I think the computer looks at ambient temp and decides whether or not defogging should be on.

Performance hit? Hard to tell. My Miata actually jolts when the AC comes on, the V-6 Santa Fe performed noticably better with it off, as did the V-8 Dakota I had before that. On this one, I think I've noticed a little "bump" when it kicks in, but it's slight enough for me to wonder if it really was the AC or something else. More experimentation needed. From a strictly logical standpoint, if you're requireing more work from the engine for a given throttle setting, there would be a performance hit.

MPG hit? Probably, enough so that I haven't been running with it in full Auto lately, since it's turned cold. In the summer, I'm sure the hit would be far less than running with the windows open.
 
Just so you know...

In the manual, page 6-8, for the Manual Type, the notes say:

"In the (feet only), (defrost), or (feet/defrost) position, the air conditioner is automatically turn on (however, the indicator light does not illuminate) and the outside air mode is automatically selected to defrost the windshield. In the (defrost) or (feet/defrost) position, the outside air mode cannot be changed to recirculated air mode."

Under fully automatic type:

Pressing auto results in the car automatically setting A/C or A/C ECO selection.

What you said about "semi-automatic" seems to be correct. On page 6-12 it says:

"AUTO switch indicator light
  • When on it indicates AUTO operation, and the system will function automatically
  • When off, it indicates the operation of other switches such as the mode selector switch, fan control dial, A/C switch and windshield defroster switch. Other functions will continue to operate automatically."

About the car using A/C automatically, page 6-12 says:
  • "Selection of A/C and A/C ECO is done automatically. Althought air conditioning and defogging ability is reduced, the A/C ECO function is designed to economize use of the air conditioning system.
  • The air conditioner may not function when the outside temperature approaching 0C (32F). (Indicator remains on even when system is off.)"

Certain things in the section about Automatic Climate Control are not mentioned. Like hitting defrost automatically turns the A/C on and illiminates your ability to select recirculate mode. That leads me to believe that some of the explaination from the Manual Control section carry over to the Automatic Section... which makes it all the more confusing.

My biggest complaint in all of this is the fact that apparently, sometimes the A/C comes on but the light doesn't light up, and sometimes the A/C light is on, but it's not using A/C. I'd be happy with an accurate indicator. I'd like to be able to make smart choices to economize on gas mileage.

I'll be tracking my MPG both ways. I did read in another forum that Automatic Climate Control did effect at least one person's MPG negatively.
 
CXRabbit said:
Just so you know...

In the manual, page 6-8, for the Manual Type, the notes say:

"In the (feet only), (defrost), or (feet/defrost) position, the air conditioner is automatically turn on (however, the indicator light does not illuminate) and the outside air mode is automatically selected to defrost the windshield. In the (defrost) or (feet/defrost) position, the outside air mode cannot be changed to recirculated air mode."

Under fully automatic type:

Pressing auto results in the car automatically setting A/C or A/C ECO selection.

What you said about "semi-automatic" seems to be correct. On page 6-12 it says:

"AUTO switch indicator light
  • When on it indicates AUTO operation, and the system will function automatically
  • When off, it indicates the operation of other switches such as the mode selector switch, fan control dial, A/C switch and windshield defroster switch. Other functions will continue to operate automatically."

About the car using A/C automatically, page 6-12 says:
  • "Selection of A/C and A/C ECO is done automatically. Althought air conditioning and defogging ability is reduced, the A/C ECO function is designed to economize use of the air conditioning system.
  • The air conditioner may not function when the outside temperature approaching 0C (32F). (Indicator remains on even when system is off.)"

Certain things in the section about Automatic Climate Control are not mentioned. Like hitting defrost automatically turns the A/C on and illiminates your ability to select recirculate mode. That leads me to believe that some of the explaination from the Manual Control section carry over to the Automatic Section... which makes it all the more confusing.

My biggest complaint in all of this is the fact that apparently, sometimes the A/C comes on but the light doesn't light up, and sometimes the A/C light is on, but it's not using A/C. I'd be happy with an accurate indicator. I'd like to be able to make smart choices to economize on gas mileage.

I'll be tracking my MPG both ways. I did read in another forum that Automatic Climate Control did effect at least one person's MPG negatively.

I have found that my MPG is much improved when I take the climate control out of automatic and prevent the A/C from running unless I want it to. I have improved my MPG by 3-4 mpg by taking this approach. When I first got mine I was getting about 16 with city driving. By controling the A/C myself I can get 19-20 for the same driving in the city...
 
It also states that you can push the auto button and then the A/C button to run the climate control in Auto-Econ mode. ;)
 
CX7andMiata -- interesting to know... I'll be tracking multiple ways and will report my findings also ;)

Offset -- Where does it state that? Also, everything with the climate system is a bit confusing because, for example, if you hit auto and defrost+feet is selected and A/C is on, even if you hit the A/C button to turn off it might not really be off. The books states the A/C is always on for this mode (and the defrost only, or feet only mode), even though the light is off.
 
offset_98 said:
It also states that you can push the auto button and then the A/C button to run the climate control in Auto-Econ mode. ;)

I couldn't find an explanation of "A/C ECO" mode either, but it sounds like, from your comment, that it's pretty much what we want--auto temp control in cool weather without the a/c compressor engaged.

Sigh...the Miata has two levers-and-cable and a rotary fan switch with a built-in a/c button. Searing heat to moderate cold. I've spent more time in the last month trying to figure out the -7's system (including RTM) that I have in the last ten years operating the Miata's. Is this the onset of Oldfartism?
 
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