How The Dual-Zone Climate Control Works

Thanks, Craig, for the great writeup! The bit on the AC was especially useful. We've had a few -25F or colder days this winter, and I was baffled as to why the car would turn on the AC. (A note: when it's double-digits below zero, warm up the windshield a bit before turning on the wiper heater. I didn't and won a craked windshield right along the top of the heater. Also, I was interested to see that the invoice price of an OBXT heated windshield from ABRA is $2400! They billed my insurance about $1200 installed.)

 

This is probably a long shot, but is there any way to shift the temperature range of the ACC? Even 66 is too warm when dressed for -25. 55-75 would suit me much better.

Oops... one more question: Does anyone who lives in a warmer climate than me (I haven't seen temps about 35F since buying my OBXT in December) know how much the AC affects mileage, if at all?

Hi there, if you're windshield cracked without any rock impact it should have been a warranty issue, not an insurance issue...

 

It is not normal for it to crack even in extreme cold (I used mine in -22F).

This is probably a long shot, but is there any way to shift the temperature range of the ACC? Even 66 is too warm when dressed for -25. 55-75 would suit me much better.

 

 

I think we could figure out a way to trick the system into "scaling" the range in the middle, but that 65/66 jump is always going to be a problem.

 

I also agree that 66 can be too warm in many cases, especially when I am driving to go skiing and all duded up in my ski clothes. What I often do is turn the fan off and just let the vent flow push through at the 66 setting. It will still trickle hot air out, but it's not too warm. That combined with the seat heaters usually works OK.

 

I think my wife's Acura goes down to 60 or 55, which would work better for me.

 

Craig

 

EDIT: maybe there's a way to throttle back the coolant flow leading into the heater core???

Thanks for the post- I found it very useful as a new owner, and it explains the A/C being on in the morning when it is 42 degrees out.

 

Much appreciated.

I've got an issue with the temp distribution. My LGT seems to cook my feet, but blow cold air out the top. I wish I could just let a trickle of fresh air come out the window vent. Does anyone know of a solution to this problem?

 

Thanx

i have to agree that this is a good post well done and thx for taking the time to do that

So yesterday was a pretty warm day in Chicago. It happened that I took a leisure drive from Chicago to Gurnee and I had to make use of the air conditioning.

 

First off...with both dials on 65 and the AC turned on...the air was still very warm.

Second...if I set it up for recirculation inside the car...the inside of the car quickly becomes too warm.

Third...if I bring in outside air it will cool down...but nowhere near my minivan levels. I mean I am pulling 2 deg C at the vents in my minivan while on recirc.

 

The recirc. doesn't seem to help cool down the interior, it will fog up the windows if used with warm air what not. Am I doing something wrong or ? Might I say I was in full manual mode...don't mess with AUTO cause I hate it.

 

And also what can i do about the interior dust. Someone please link me to that cabin air filter thread...or is it just my interior that is so dusty .

Did you read the first post in this thread?

 

It has the answers to your questions...

Dude...what part of my explanations you do not understand and what part of these explanations clears up my issues ?:rolleyes:

 

One thing that seems to bother people is that air conditioning (AC) runs almost all the time in AUTO mode. Well sort of. The AC compressor has a clutch, and it actually cycles on and off as needed (cars have been doing this for years). It cools the air in warm weather, and dehumidifies the air in cool weather (or when defrost is activated). All the while, the AC indicator remains lit. This simply indicates that AC can come on if needed, even though it may not be on full time. In extremely cold weather, the AC indicator will stay off until the engine warms up because it is too cold for the compressor to run. Once the engine warms up or the ambient temperature increases, the AC indicator may come on, again, to indicate that AC can activate if needed.

 

Another thing that bothers people is the fact that there is a world of difference between the temperature setting of 65 and 66. As discussed above, 65=LOW, or no heat added. So while 66 indicates a set temp of 66F in AUTO mode and it's the lowest setting for heat in the manual mode, 65 indicates "no heat". In AUTO mode, 65 actually translates to maximum cool (try it in the summer, it will frost your tootsies off). I really think Subaru should have labeled 65 as "LOW" (and 85 as "HIGH") similar to Acura.

 

What part of 65 setting translates to maximum cool should I disregard ? I tried it as you said it...the car does not want to cool down. AC does not work. On 66 cyling the air, it is horrendous. On 65 cyling the air is mildly inhumane. If I bring outside air, the experimental drivers inside will not die of heat stroke...for now because the air is still cool. AUTO, MANUAL mode, this car doesn't cool.

That says in AUTO mode it is maximum cool. You said you were using it in MANUAL mode.

 

If that doesn't work, then you clearly have a defective A/C.

Yeah, in AUTO mode, 65 will seriously crank out the cold -- it's MAX AC. Try that out, and if it doesn't cool the interior down dramatically then something is wrong.

 

In manual mode, you can still tweak it to get the AC cranking cold, but I am not confident we can communicate on that properly since there are a lot of variations. AUTO, on the other hand, should be universal.

 

Craig

Is there any way to make the dual zone feature change in sync with one another? I do most of my driving alone, and sometimes it is annoying to have to change both knobs to the temp that I want...

 

thanks

Heh heh, I asked the same question during a test drive and was told by the salesman, (paraphrasing, and putting words to his tone of voice), "No, but is it really that much harder to twist 2 knobs than 1 knob?" I agree it would be a nice feature, and seems like it would have been trivial for them to design in. Oh well.

 

-Matt

At least he told you... during the test drive, my salesman told me that there was a way to do it, but he could not remember how. then i forgot about it until I owned the car for three days... I called him to ask how to do it, and he said that he must have gotten it confused with the Nissan Altima, which has a button to do it.

 

Ohh, well, hardly something that would have kept me from buying the car, but you're right, it would be nice... My mother said that I should get married so that I have someone to sit there and change it...

I guess I have a defective AC as I have the same issue as F1anatic. Today it was not that hot maybe 60 degrees but the car sat in the sun all day while I was at work. I got inside and it was warm in there at least 75 degrees maybe a bit more. Anyway I set it to auto and dropped the dial to 65 the fans went to max and warm air comes out. I try manual again at 65 and warm air. I change to fresh air instead of recirc. and the air cools a bit due to the outside air being cooler. As soon as I go to recirc it was warm agian. I noticed a problem over the weekend when it was raining at night and the windshield fogged up. I dropped the temp to 65 and put it on defrost and warm air kept coming out. This is when I started to think there may be a problem. Think I may have to visit the dealer?

My AC wasn't working when I bought the car, I called the dealership and they never connected the AC plug in the fusebox in the engine compartment. The car is delivered from the factory without it connected to keep the battery fresh.

 

Open the black plastic fusebox behind the battery, and plug in the plug that is upside down. Takes a couple of seconds and no tools.

HAHAHA !! I just found this out on my own tonight. I saw the compressor not kicking on so I opened up the fusebox. There sat a blue relay with the prongs facing up. I take it out and flip it over putting it in it's resting place and bingo the compressor comes on instantly. Dam fewlz at the dealership................. I put a pocket probe thermometer in the dash vent and the temp got to 49 degrees. My buddies 97 Maxima with 97,000 miles cranked out 42 degree air. Wonder if the system needs to run a bit otherwise the system is still not up to snuff. The air temp coming out before the relay was fixed was 60 degrees with it on max cold (65/65 left it on recirc.

From the Original Post:

[in Manual Mode] "65=LOW corresponds to no heat added"

 

This statement doesn't seem to be true on my car. Once the engine has really completely warmed up, with the fan on outside air and the dial set to 65, the air coming in the vents is noticably warmer than the air coming in through the windows. I know it might not be possible to bring air in through the engine compartment without transfering some heat to it, but it seems like the air is being warmed quite a bit. In my previous car the air coming in through the vents was pretty close to outside temperature even with a hot engine.

 

Has anyone else noticed this on their car?

 

BTW, mine is an '05 Outback XT, but I'm assuming that this issue would be the same for the Legacy.

I should clarify that to mean no heat added from the heater core, which is what controls the HVAC temp directly. There could very well be carryover heating from the engine, depending on where the air gets taken in and routed.

 

I assume you were not on AUTO right? 65F on auto is maximum arctic mode.

 

CRaig

Thanks for this post and its clear explanation.

 

I haven't picked up my own Legacy yet (two weeks until deilvery!), but I recently bought my dad a Toyota Prius, and this post answered a lot of our questions on that AC system as well... works similarly, but without the dual climate controls...

 

Cheers.

 

Dave

On my 05 I noticed the other evening - outside 16C, control set to 23C, Auto, cool air coming in through vents, face and feet(think ac was running); change set temp to 25C, warm air on feet, face level cut off.....Does that mean that it sensed interior was warmer than 23, and needed cooling, and that at 25C set, it needed warming? Ie interior was sensed as 24C? It didnt feel like - usual comfort level for me is ~21C

Is this a symptom of the lack of flow through the sensor , where fore there is a fix listed on scooby for Forrester or similar?

jp

My AC wasn't working when I bought the car, I called the dealership and they never connected the AC plug in the fusebox in the engine compartment. The car is delivered from the factory without it connected to keep the battery fresh.

 

Open the black plastic fusebox behind the battery, and plug in the plug that is upside down. Takes a couple of seconds and no tools.

 

Yeah, I found this out the hard way. I bought my car in Lancaster (high desert for those who know SoCal). No A/C on the test drive and I guess they never found it when prepping the car for delivery. So I had a nice 50 mile drive home and of course it was hot as hell that day:mad:

 

For the record I didn't want to leave it there for them to fix since I would have had to make another 70 mile (one-way) trip to get it.

the outside temp was 67, inside the car was 72, the acc was set on 65 manual. The air coming out of the vents was 87 degrees:eek: .

 

i do not need to cook food in the car,

something is wrong and SOA better find a fix.

my car does the same, something is defective, because this much heat should not be getting in the air vents or intake, which is under the hood. what rocket scientist put the fresh air intake under the hood?