Highlander Hybrid Air Conditioning Questions

nimhrodnimhrod Member Posts: 49
edited July 2014 in Toyota
I've owned my '96 Forerunner since new, and one of the things that's always impressed me is the "HVAC" system. The heater in that Toyota will almost burn your hands if you leave them against the vent. And the A/C has plenty of volume and is cold as can be. Does the new electric a/c blow as much volume, and is it as cold as other Toyota's?


  • ulevulev Member Posts: 57
    My 1990 4 Runner does the same.

    The heat is welcomed in the Winter..when it warms up the entire truck in minutes.

    I still have it....for sentimental reasons...
  • ulevulev Member Posts: 57
    To answer your second question.

    The HH AC does a good job in maintaining an even, temperate climate, in side.
    It does not 'blow you out' as does the ICE driven prior Toy Models, but I have felt comfortable manually (Non Ltd) setting the temp.
    I have had occassion to redirect the vents as it has gotten cold on exposed skin when directed on it.
  • fizbanfizban Member Posts: 42
    On the Limited edition, you can set put the temp in "Automatic" and set the thermostat. Then, the system just takes over. If it's got a lot of work to do, it'll turn the fan on high and gradually reduce it as it approaches your desired temperature setting. When it's got itself set on high it's pushing a lot of cold air your way.
    To help speed the cooling effect, it puts the system on internal circulation. I tend to not like the additional fan noise in that mode, so I manually put it back to external circulation. I've owned a lot of Toyotas and this one's climate control is just as good, if not better, than the others.
  • poodlgalpoodlgal Member Posts: 13
    I am admittedly ignorant about these things, but am curious about the following:
    1. Wouldn't turning off the heater and fan shut off the A/C compressor?
    2. Would you expect the A/C compressor to have such a drastic effect on mileage (below 20 MPG)??

    Thanks for your thoughts.
  • wwestwwest Member Posts: 10,706
    Yes, anytime the climate control is off, depress the off button, the A/C will be off.

    On a "normal" car at highway cruise it is not unusual for the A/C to account for as much as 10% of the fuel burn on a hot summer day and 5% during the winter months with the average OAT well above freezing.

    In city stop and go it will be worse.

    Your ICE must run for four reasons.

    1. Motive force.
    2. Battery charging.
    3. Cabin heat.
    4. Maintaining the catalyst at optimum operating temperature, ~800F.

    Absent manually turning the A/C off the incoming airflow will first be chilled and then at least a portion must be reheated to maintain the cabin at or near our comfort level setpoint.

    It seems to me that converting the compressor to electric drive was needless if you still have to run the ICE as an integral part of climate control, heating or cooling.

    Overall it seems to me that climate control as implemented on the Highlander and Rxh will likely reduce the fuel economy more than on a normal vehicle.
  • bob2006bob2006 Member Posts: 6
    I just got my new HL, and I was trying to figure out the AC indicator. After I push AUTO, that button light comes on, fine that is clear, then i push the Climate button, and the screen brings up all the climate controls. The AC indicator in the touch screen has a yellow bar, I push the nav screen button and it turns blue. OK so I assume that yellow indicates that that the AC will turn on if needed, and the blue indicates that I have manually turned off the AC.

    Can anyone confirm this? Is a yellow bar on (automatic), and blue bar off?

  • mdchachimdchachi Member Posts: 275
    Yes, that's true. It's supposed to look like the Auto button you just mentioned. Yellow is lit (on) and blue is unlit (off). It doesn't necessarily mean "automatic" because you could have AUTO shut off but you could manually set the fan speed and turn A/C on, can't you?
  • bob2006bob2006 Member Posts: 6
    Thanks md....

    I searched the manual and found where it tells you one can turn on and off the AC, but it did not say which was which. I am pretty sure you can have manual control over the AC and fans if you want. It is just too cold here in San Diego (if you can believe that), to test the AC.
  • cdptrapcdptrap Member Posts: 485
    Hi Bob2006,

    Geeting snow in "sunny" San Diego today? Strange weather in Northern CA so far, 3-inches of snow around our place and our HH has gone through sleet, hale and snow today and last night, fourth time this season. More tonight, tomorrow and tomorrow night.

    Drive safe.
  • wwestwwest Member Posts: 10,706
    The RX400h and HH have several custom setup parameters which owners should be aware.

    The A/C compressor can be disabled indefinitely so it does not operate automatically in normal automatic mode or in defrost/defog/demist mode.

    With these settings the A/C can be turned off manually and will remain off indefinitely until it is manually turned back on. Once turned on it will operate continuously just as it otherwise would. As shipped the A/C will also operate automatically with the defrost/defog/demist function with no indication to the driver of same.

    Operation of the A/C during the winter months is needless except for the remote possibility of it being able to dehumidify the incoming airflow to a level which prevents windshield fogging. Since most occasions of windshield fogging is the result of system "upset" (loading a couple of cold, wet, and sweaty snow-skiiers with their soaked clothing, etc.) or in many cases the result of A/C operation being discontinued due to declining OAT.

    Intermittent use of the A/C only during defrost/defog/demist mode is a catch 22 of itself. In the rare case wherein the incoming air's dewpoint is such that the A/C can provide a reasonable level of dehumidification when the normal operation mode is resumed the A/C operation will stop. That will result in all of the previously condensed moisture remaining on the evaporator vanes to evaporate into the incoming airstream often resulting in a reoccurance of windshield fogging.

    Another new feature is that the dealer can change a custom setting wherein the system will not automatically switch from footwell, heating mode, to dash/panel outflow, cooling mode(***). The cabin temperature control only responds to air temperature or the sun's radiant heating effects. The human comfort equation is much more complex than can be resolved by just those two parameters.

    The effects of radiant heating (or lack thereof) from the exterior and interior "landscape" surrounding your body also play a very great part in establishing human comfort. On a cold dark night with the landscape covered with snow the system, driven only by its measurement of interior, cabin air temperature, will almost always shift, first, into mixed footwell/dash outlet mode, and then into full cooling mode, dash airflow outflow mode, once the cabin temperature closely approximates your manual temperature setpoint.

    As many of you have already no doubt noticed, that can be quite discomforting to you and your passengers.

    But there is yet another important aspect of this feature, heating/cooling mode parameter setting. In full cooling mode, which the system would otherwise almost always default into as the cabin temperature reaches your setpoint, no warming airflow reaches the interior surface of the windshield.

    It can become extremely dangerous to allow the windshield interior surface temperature to decline due to the onrushing COLD outside airflow during wintertime operations. Keeping the system in footwell, heating mode will result in a significant level of airflow being continuously routed to the windshield thereby keeping it well above the dewpoint of the cabin atmosphere.

    You may note that in your owners manual is a new (as of 04?) note of caution. Since the A/C will shut down automatically if the outside temperature should decline to or below the freezing level the newer Denso climate control systems will automatically switch a portion the system outflow to the interior surface of the windshield just as the A/C is disable.

    A bit of shutting the barn door after the horse has galloped off down the road, that is.

    Or actually it can be very much worse.

    When the A/C is disabled in this manner any previously condensed moisture remaining on the evaporator vanes, 10,000 square inches thereof, will begin to evaporator into the incoming airstream. Absent your having had the dealer make the parameter change from the factory default the windshield interior surface may very well have already been chilled to well below the dewpoint of the super-saturated airstream now routed, automatically, in its direction.

    But never fear, there is yet another parameter that the dealer can set for you that will help to defog/demist the windshield. The dealer can set a custom parameter which will cause the blower speed to automatically increase when you select the defrost/defog/demist mode.

    Now if we could just get them to recognize that the airflow heating level to the windshield should also go up simultaneously.................

    *** I would be very interested in the results if anyone chooses to have this parameter set to prevent an automatic switch to cooling mode. I assume one can still manually switch to cooling mode. My question is does it operate in the same way as the A/C disable custom parameter?

    If I manually switch to cooling mode will it thereafter automatically switch back and forth as it otherwise would until I manually turn cooling off?
  • discussion1discussion1 Member Posts: 103
    Can you put it in less technical terms? Such as what I must do?

    Our experience is when defroster is ON, the blower goes high and blows hard until we shut off. It clears everything quickly.

    On cold days, with outside temperature at low 30's, internal breath will slowly fog up the windshield. We manually set temperature to warm and select vent+floor and run the fan low or 1. This keeps the windshield clear and interior comfortable.
  • wwestwwest Member Posts: 10,706
    Sorry, I didn't explain very clearly.

    Until the cabin has warmed to a level at least close to your temperature setpoint it is very typical for the blower speed to increase, even dramatically if the cabin is really cold.

    Once the cabin has warmed to the point wherein it will begin the sequence of automatically re-routing outflow air from the footwell to mixed and then to dash only there will be very little or not reaction to switching to defrost/defog/demist mode.

    The custom parameter setting would/will result in the blower speed rising when you activate defrost/defog/demist mode regardless of cabin temperature.

    During the winter months you can help to prevent inadvertent windshield fogging by being sure the A/C compressor is NEVER used and by being sure to keep the system's air outflow mode in footwell ONLY.
  • larry70larry70 Member Posts: 3
    AI have had my HiHi for 1 1/2 years. Now,there is a musty smell inside that is not caused by the carpet or mats ever being wet. When the a/c is turned on, for the first blast of air, it smells. The dealer changed all the filters, with no solution.
    Anyone else have this problem? Maybe the a/c line is clogged or something.
  • larry70larry70 Member Posts: 3
    The braking question was not supposed to be mixed with the mildew question, but I messed it up.

    CDTRAP - you are exactly correct on all your descriptions of the braking issue. I am hoping it is not a safety issue.

    On the musty smell, the dealer's service writer was the only person of 3 of us who could not smell it. The dealer doesn't have a clue, other than to charge me $85 to replace the filters that didn't seem that dirty to me, but then, I am only a dumb car owner.
  • hidesertdihidesertdi Member Posts: 1
    How often is it recommended to have the air conditioner filter checked? Is that part of the maintenance of an oil change at the dealerships? We're smelling something like a dead animal from our engine area. We cannot see any critters in grill or otherwise. When I check my air conditioner air filter today, it was overflowing with all sorts of debris. I know for a fact it was changed last year and I just had my oil changed at a dealership a couple of weeks ago (that's why I was wondering if they check the filter at oil change). Has any body else had problems with dead animal smells?
    thanks for your time!
  • monte8monte8 Member Posts: 75
    I have not had the problem, but if you live in (or drive through) an area with large concentrations of flying insects, they could end up in the cabin air filter. Some insects really stink. Around here (prairie pothole region of North Dakota) we have "fish flies". These will turn the front end of your car almost black (it looks like your car has a 3 day old beard) in minutes. And it smells bad. :P
  • wwestwwest Member Posts: 10,706
    edited May 2010
    Living out in the woods as we do I have had mice, and squirrels, build nests in many of our cars over the years. It is not at all unusual to find a dead mouse somewhere in the HVAC fresh air intake system/path. The most common entry point seems to be around the windshield wiper shaft where it comes up through the cover just below teh bottom of the windshield.

    To inspect for a dead animal you must remove that cover and then probe blindly into some of the recesses, especially the fresh air entry recess, you find there. Remove any nesting material you find there.
  • CTKarenCTKaren Member Posts: 3
    My two front floor mats and base under mats are wet lately. I think it must be related to running the AC. Any ideas why this would occur or if there is anything I can do myself to avoid a repair bill? Maybe a filter clogged from tree debris?
    Toytota Highlander Hybrid 2008
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