Highlander Hybrid Air Conditioning Questions
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?
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The heat is welcomed in the Winter..when it warms up the entire truck in minutes.
I still have it....for sentimental reasons...
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.
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.
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.
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.
Can anyone confirm this? Is a yellow bar on (automatic), and blue bar off?
Thanks
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.
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.
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?
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.
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.
Anyone else have this problem? Maybe the a/c line is clogged or something.
Larry
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.
thanks for your time!
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.
Toytota Highlander Hybrid 2008