HVAC off but still getting warm air?

[dingo]

Hey fellas, just wondering if anybody else experienced this. I noticed that on the driver's side leftmost (on dash, closest to window) air vent there is sometimes warm air coming out. This is with the HVAC and climate contol completely off. The other vents are also open but do not blow warm air. The recirc switch is also OFF. I'm just trying to figure out why this particular vent gets warm (it's not uncomfortable or hot by any means, just warm air). This doesn't happen all the time, and when it does the force of air is like driving normally with fresh air coming in. Just want to know where the heat could be coming from. Could it be from the ambient temperature from the engine bay working its way in somehow? I dunno, I got nuthin. Any ideas why this is so? Is this cause for a stealer visit? Thanks in advance.

 

[Northof49]

Air still flows through the vents even when the system is off in every vehicle. If you were using the heater before turning the system off.....the air would be warm.

Not sure why one vent is warmer than the others, but I highly doubt it's anything to worry about.....probably just the way the air flows.

If the HVAC works normally when it's on, I definetly would not bother going to the dealer.....they'll just think you're nuts :arrow:

 

[TitaniumToy]

Yes Like Northof49 said "If you were using the heater before turning the system off.....the air would be warm". I find this anoying myself, because you cannot adjust the temperature without turning on the fan.

If you want fresh unheated air. Turn on the fan, adjust the temperature to the coolest setting, and then turn the fan back off.

 

[JB.]

I find this anoying myself, because you cannot adjust the temperature without turning on the fan.

Yeah, the HVAC is the not one of the 4Runner strong points.

If you want fresh unheated air. Turn on the fan, adjust the temperature to the coolest setting, and then turn the fan back off.

Then blow your whistle, honk your nose, and run around the little red fire engine.

 

[NoSpeedLmt]

Put the recirculation on and the air will stop flowing.

 

[CVsGX470]

Hey fellas, just wondering if anybody else experienced this. I noticed that on the driver's side leftmost (on dash, closest to window) air vent there is sometimes warm air coming out. This is with the HVAC and climate contol completely off. The other vents are also open but do not blow warm air. The recirc switch is also OFF. I'm just trying to figure out why this particular vent gets warm (it's not uncomfortable or hot by any means, just warm air). This doesn't happen all the time, and when it does the force of air is like driving normally with fresh air coming in. Just want to know where the heat could be coming from. Could it be from the ambient temperature from the engine bay working its way in somehow? I dunno, I got nuthin. Any ideas why this is so? Is this cause for a stealer visit? Thanks in advance.

Yep, drove me nutts too. You have to make sure that you turn the temperature down to a lower setting before turning the system off or the HVAC system seems to continue to heat the air to your previously decided temperature. Watch out, if you go down too low the system will close the circulation on you even if you have the system off and then you will have no air coming thru your vents. I used to set mine to around 65. I believe the next setting down is, "low," and that will close your vents.
CV

 

[Kmvreter]

Yeah, the HVAC is the not one of the 4Runner strong points.

I don't know about that. I set mine to auto at 21.5degC and turn the A/C on/off as required (winter vs. summer.) It has a quirk with the recirc. coming on at startup depending on the temp but once you get used to it, it works great. Much better than anything I've owned before (all manual lever systems.)
I imagine that if you were spoiled and had a better auto system in a prior vehicle (or if you are technologically challenged) then you might have issues with the T4R system (or life in general.)

 

[Koz]

I don't know about that. I set mine to auto at 21.5degC and turn the A/C on/off as required (winter vs. summer.) It has a quirk with the recirc. coming on at starup depending on the temp but once you get used to it, it works great. Much better than anything I've owned before (all manual lever systems.)
I imagine that if you had a better auto system in a prior vehicle (or if you are technologically challenged) then you would have issues with the T4R system (or life in general.)

:iagree:

Koz

 

[dingo]

Watch out, if you go down too low the system will close the circulation on you even if you have the system off and then you will have no air coming thru your vents. I used to set mine to around 65. I believe the next setting down is, "low," and that will close your vents.
CV

Wow, I did not know that! Learn something new everyday. I guess I'll just ignore it then. Strangely, the leftside vent gets warm without turning on the heat initially at all in some cases. I'll pay closer attention the next time and see what happens when I turn it down lower. 6 months of ownership and I'm still not use to how the HVAC system works, I guess I am too use to the manual levers and systems of oldschool. I've been also trying to conciously memorize the button locations by touch alone so that I can press them without looking. I still find myself looking down sometimes.

On a sidenote, I was looking at the HVAC knobs, the 4WD drive selector switch bezel, the dash dials' backround bezel, and saw a common design theme with the Limted and SR5's alloy wheels. They all kind of look alike. A design theme based on five spokes for the most part (not so much the guage cluster but similar). I also found out that the rubber pad lining on the bottom of the driver/front passenger center cupholder comes out for cleaning (not the divider but the actual dimpled pad)...cool. I guess you notice these small nuances more when NOT driving. Ok, sorry for straying off-topic.

Anyway, thanks for all the suggestions, guys. I'll experiment more with the climate controls.

 

[Kmvreter]

6 months of ownership and I'm still not use to how the HVAC system works, I guess I am too use to the manual levers and systems of oldschool... I'll experiment more with the climate controls.

That's how I felt. Now I set it to Auto, pick my temp and turn the A/C on or off depending on the season. I rarely use the recirc so when that comes on at startup I just turn it off. I don't touch the fan speeds or temp; let the auto adjust as it needs to.

 

[JB.]

I imagine that if you were spoiled and had a better auto system in a prior vehicle (or if you are technologically challenged) then you might have issues with the T4R system (or life in general.)

Ouch. No good deed goes unpunished. Still, I hope you enjoyed the trip.

I'll take the automation where it increases safety, functionality, and does things I can't possibly do - VSC, for example - but I'd like full control over HVAC just like I want same for, say, seating and window positions.

 

[atomic punk]

I imagine that if you were spoiled and had a better auto system in a prior vehicle (or if you are technologically challenged) then you might have issues with the T4R system (or life in general.)

Double ouch.... Admittedly, lever HVAC systems suck (or blow if you want the pun intended), but so does a system where you need to push a single button 21 times to go from Max Heat to Max AC, or hold the button and wait for the temps to increase s-l-o-w-l-y.

And before anyone replies with the next obvious statement: YES, here in the northeast, it's not uncommon to change the settings from one extreme to another in the same day.

Call it personal preference, but I'd rather have seen a knob there.

 

[Northof49]

Double ouch.... Admittedly, lever HVAC systems suck (or blow if you want the pun intended), but so does a system where you need to push a single button 21 times to go from Max Heat to Max AC, or hold the button and wait for the temps to increase s-l-o-w-l-y.

And before anyone replies with the next obvious statement: YES, here in the northeast, it's not uncommon to change the settings from one extreme to another in the same day.

Call it personal preference, but I'd rather have seen a knob there.

You don't have to.....I have never done that once and have definetly needed both extremes in the same day.

As evidenced by your post, the people that think the system sucks don't know how to use it properly.

 

[Kmvreter]

Double ouch.... Admittedly, lever HVAC systems suck (or blow if you want the pun intended), but so does a system where you need to push a single button 21 times to go from Max Heat to Max AC, or hold the button and wait for the temps to increase s-l-o-w-l-y.

And before anyone replies with the next obvious statement: YES, here in the northeast, it's not uncommon to change the settings from one extreme to another in the same day.

Call it personal preference, but I'd rather have seen a knob there.

I'll take the pun (got to keep laughing.)
I agree with Northof49. I also live north and east and might see drastic shifts. No need to go from max heat to max A/C. It's a thermostat (working on the same principles as a house therm.)Set the temp in auto and let it do the work. Just click the A/C on or off. One push, not 21.

 

[Koz]

You don't have to.....I have never done that once and have definetly needed both extremes in the same day.

As evidenced by your post, the people that think the system sucks don't know how to use it properly.

:iagree:

Koz

 

[atomic punk]

Agreed, and I do use the AUTO function at times, but it doesn't work for all circumstances. Ie: it won't automatically defrost my winshield when I need it to, or switch back to dash vents when I need it to. It's quirky.

Northof49: as evidenced from your post, you have no idea how to read an entire post before passing judgement. My last line in my previous post was the conclusion, not just "SYSTEM SUCKS" without backing up. Now go read it again.

Not for nothin', but my comparably priced Acura TL's HVAC blows this one away (pun intended this time), but I didn't want to write that because I might offend sensitive readers such as yourself. This one is adequate though.

But a KNOB would have been better....

 

[toto]

Here are a few things I've learned about Toyota's auto climate control that might help explain its behavior.

- Warm air comes out by the floor, and cool air comes out the dash vents. That's the most efficient way to run both - make the warm air rise so that the interior warms evenly, and similarly, make the cool air sink.

- The air conditioning compressor almost always appaers to be on, as indicated by the light on the A/C button. As long as the outside temperature is above freezing, the system will use the A/C as it feels necessary to help dehumidify the air. Even in the middle of winter, it will blow dehumidified warm air to try to keep the windows from fogging up.

- You can leave the system in "Auto" and press the defogger button. That will override the program and start blowing dehumidified air at the windows. Press the defogger button again to go back to regular operation.

- On warm days when A/C is necessary, the computer turns on recirculating mode at first because that will cool the car off faster - it's more effective to keep cooling air that you've already tried to cool, rather then fresh hot air. Once the engine is up to speed and the A/C is running at full capacity, it will automatically turn off the recirculating mode and go back to fresh air if you didn't press the button to force it to recirculate.

I've found the auto climate control to be very effective in deciding the best course of action without much intervention. Here in Chicago, we've got a saying that if you don't like the weather, wait 20 minutes. It's not always that goofy, but it's very common to change temperature by 20 degress or more in a matter of a couple of hours, or to have snow or rain while the sun is shining.

If you're not used to auto climate control, or it doesn't do things the way you would control the air yourself, then I know it takes patience to adjust to its behavior. My dad got a car with climate control for the first time in his life a couple of months ago, and he hated it at first. Once he got used to it, he found that it really doeswork most of the time. Basically, it does exactly what the manuals have told you to do with the knobs for years.

 

[atomic punk]

Excellent comprehensive write up toto. Thanks....

Referring to this:
- You can leave the system in "Auto" and press the defogger button. That will override the program and start blowing dehumidified air at the windows. Press the defogger button again to go back to regular operation.

Q) what if my previous setting is Auto @ 65 from yesterday afternoon because it was warm, and I wake up this morning to find my windows iced over... now will just hitting the Defrost button give me a HI (85+) degrees on the defroster, or will it be 65? coming out of the defroster.... from my experience, it won't automatically change to HI heat.


My yearning for a knob is not to be old-school, but, rather, to save precious milliseconds. Call me impatient, but I'd rather scroll from 68 to 85, and not have to taptaptaptaptap... it's the same reason why I prefer my head units to have a volume knob as opposed to two volume buttons for up/down.

 

[CVsGX470]

Here are a few things I've learned about Toyota's auto climate control that might help explain its behavior.

- Warm air comes out by the floor, and cool air comes out the dash vents. That's the most efficient way to run both - make the warm air rise so that the interior warms evenly, and similarly, make the cool air sink.

- The air conditioning compressor almost always appaers to be on, as indicated by the light on the A/C button. As long as the outside temperature is above freezing, the system will use the A/C as it feels necessary to help dehumidify the air. Even in the middle of winter, it will blow dehumidified warm air to try to keep the windows from fogging up.

- You can leave the system in "Auto" and press the defogger button. That will override the program and start blowing dehumidified air at the windows. Press the defogger button again to go back to regular operation.

- On warm days when A/C is necessary, the computer turns on recirculating mode at first because that will cool the car off faster - it's more effective to keep cooling air that you've already tried to cool, rather then fresh hot air. Once the engine is up to speed and the A/C is running at full capacity, it will automatically turn off the recirculating mode and go back to fresh air if you didn't press the button to force it to recirculate.

I've found the auto climate control to be very effective in deciding the best course of action without much intervention. Here in Chicago, we've got a saying that if you don't like the weather, wait 20 minutes. It's not always that goofy, but it's very common to change temperature by 20 degress or more in a matter of a couple of hours, or to have snow or rain while the sun is shining.

If you're not used to auto climate control, or it doesn't do things the way you would control the air yourself, then I know it takes patience to adjust to its behavior. My dad got a car with climate control for the first time in his life a couple of months ago, and he hated it at first. Once he got used to it, he found that it really doeswork most of the time. Basically, it does exactly what the manuals have told you to do with the knobs for years.

:iagree: :bowdown:

excellent explanation.

 

[toto]

Referring to this:
- You can leave the system in "Auto" and press the defogger button. That will override the program and start blowing dehumidified air at the windows. Press the defogger button again to go back to regular operation.

Q) what if my previous setting is Auto @ 65 from yesterday afternoon because it was warm, and I wake up this morning to find my windows iced over... now will just hitting the Defrost button give me a HI (85+) degrees on the defroster, or will it be 65? coming out of the defroster.... from my experience, it won't automatically change to HI heat.

No, the defogger button won't change the temperature setting.

But if it's colder in the car than 65 (your last set temperature), then the computer will want to turn on the heater, and that will in effect blow hot air at the windshield.

You don't have to set the temperature at low max or high max to "force" the heat or air to work with the fan on High. Let's say you leave the inside temperature at 73. If it gets warmer than that, or the computer figures it will get warmer than that based on the sunlight sensor, it will turn on the A/C, and it will turn up the fan as needed to sustain 73.

The next morning, the car will be a lot colder than 73, so if you press the defogger button, it will blow hot air at the windshield. Note that it won't blow on "High", though, until the engine warms up. That's another thing I should have pointed out.

Remember that when you set a temperature, you're not actually setting the temperature of the air coming out of the ducts. You're setting the temperature you would like it to be in the car, so the computer will turn on heat or A/C as needed to get there.