Adjusting the climate control

Yes you are correct, that's what I intended to say about the Defrost button. I was unaware the AC came on when defrost/floor was selected via the Mode button. The owner's manual says you get AC with the Defrost button but it does not mention AC with the defrost/floor setting. I have changed my previous post.

EDIT: I just confirmed that the AC does indeed come on when either the Defrost button or defrost/floor with the Mode switch are selected. Thanks for the correction Peirhead. I was able to prove this to myself by watching the HV battery Amps on the scan gauge, ICE off, while switching between modes, the AC draws quite a few amps compared to just the fan.

This is an automatic feature I don't like very well either, I wish there was a way to get defrost without AC. It's kind of a waste of energy to use AC when not required. There are a lot of times when just a bit of warm air will keep the windshield clear without running the AC unit.

 

But how does AUTO know when the windshield is foggy and needs warm air to switch modes. Mine does not seem to have that knowledge. I like Auto and appreciate how it varies speeds and keep the temp in range, but it does not keep a windshield clear not even switch modes to do so.

 

I think Ohio weather calls for manual intervention especially on defrost/foggy conditions. I used to live there and would believe that waiting for the Auto setting to do it's thing would be a waste...but only a waste of time not gas.

 

One Important Note: If you are in ECO Mode, the fan of the climate control will not ever spin at full speed, and the Air Conditioner pump will also not work at full speed either. I found this out the hard way when it was 118ºF in Palm Springs, and I could not get the car comfortable, till I bumped to POWER mode to get onto the highway and noticed the jump in blower speed. Once I did that, and went to normal mode (NonECO) the car chilled down very well. I did not put it back into ECO mode till I was further west and the temperature outside came down to a mild 102ºF. :flame:

 

Please refer to "Using the Automatic Mode" in the owners manual (pg 271).

Air outlets and fan speed are automatically adjusted according to the temperature.

Directing air flow to the windshield and floor is accomplished using the defrost mode, this manual override will turn off the Auto light. When windshield is clear you can go back to Auto.

 

I just jumped on to look for advice about windshield fogging. Thought I got the hang of it after 10 months, but the last two days tried everything with no luck. One day it was rainy and used the defogger with no luck. Last night it was cool but no rain. When the defogger didn't work, I thought I'd try A/C to take the moisture out, then tried heat to evaporate the moisture. Never had such a problem before (also have the condensation by the Trip A display). When I first took the car off the lot, I had to pull off the side of the road since I couldn't see out! Maybe it's my age

 

I had some issues with getting heat in my Prius 2010. What i do not understand is that when i turn the Temp down, it only says low and wont let me set the lower temperature. Is that normal? And when i set it in Auto, it started blowing cold air. How do i set the climate control to get heat? To make it clear, the drive was nearly 45 minutes and i could not get heat. I had to lower the fan to get less cool air. Not sure what i am doing wrong. My wife takes my kid to school every day and with the winter cold coming back to New Hampshire, it would be extremely hard for my wife to drive in the cold without heat. Any quick response is appreciated. And yes, i read the manual which is not that clear about getting heat.

 

I don't quite understand what you were referring to by "the lower temperature" you can only set one temperature. If you select Auto the auto light should come on and the system should give you heat to arrive at the temperature you have set. It sounds like all you had to do was leave it in Auto and turn the temp up to where you wanted it. The LOW indication means you have set the temperature as low as it can be set.

If it is hot out you can select Auto and push the AC button and it will use the AC to cool the car down. If you have the system in Auto with the AC on it will either cool or heat to maintain the temperature you have set.

That's how it should work unless something is wrong with it.

EDIT: It occurred to me you may have been thinking that there were two temperature settings, high and low, such as a good home thermostat would have. Unfortunately Toyota only gave us one temperature setting, I usually set mine for 72 when I want heat then have to turn it up to 78 or so when I want AC. I wish there were two settings.

 

Thanks Tom..
So what you are saying is that if i set the Temperature to 70 and set it to Auto, the temperature inside the car will be maintained at that level which is warm. The higher the temperature setting the warm the inside of the car will be. Correct me if i am wrong. But if i want to have the air blown to my face and feet i need to set to through the mode which will automatically set Auto to off. How then do i control the hot air inside. Do i need to turn the fan speed high? This is the first winter after i purchased my car and it will take some time for me to get used to this. Any help will be appreciated.

 

Thanks Tom..
So what you are saying is that if i set the Temperature to 70 and set it to Auto, the temperature inside the car will be maintained at that level which is warm. The higher the temperature setting the warm the inside of the car will be. Correct me if i am wrong. But if i want to have the air blown to my face and feet i need to set to through the mode which will automatically set Auto to off. How then do i control the hot air inside. Do i need to turn the fan speed high? This is the first winter after i purchased my car and it will take some time for me to get used to this. Any help will be appreciated.

 

When you've turned down the temperature to LOW, you're correct -- that's as low as it can go and you're not going to get heat. If you want heat, you need to move the temperature UP, not DOWN. It works just like your thermostat at home. If you turn the themostat down below 65degF, you won't get any heat. If you want heat, you have to turn it UP.

Now, let me try to address how to use the climate control. I think there are many variables and people are confusing themselves.

AUTO gives the system complete control over airspeed and direction. The system will do everything it can to acquire and maintain the temperature you requested. Typically, airflow will be through the dash vents if cooling is required, approx 90% floor/10% defroster if heating is required, and a mix of the three if something in-between is needed. Today, with the temperature at about 46 outside, 69 set inside and solar load, it was putting about 50 face/40 floor/10 defroster.

Keep in mind, it's looking at the interior temperature. So, on a day like today in Chicago, where it was cool and sunny, when I come up to the car, the OAT may be 46degF; however, the temperature inside the vehicle might be 85degF because of the greenhouse effect from the sun coming in through the windows. So, if you have the climate control set to 72degF when you start the car, it's actually going to cool the interior in order to get the temperature down to 72, even though it was 46 outside.

Having said that, there are ways to override full AUTO operation.

The A/C button will enable or disable the compressor's operation. As has been mentioned before, the compressor performs two duties: (1) cooling the air and (2) dehumidifying the air. When the A/C light is OFF, under most circumstances, the compressor will not operate. When the A/C light is ON, the sytem will vary the compressor's output to meet the cooling and/or dehumidifcation needs inside the vehicle. Turning this button off will not change any other functions in AUTO, with the exception of reverting to the FRESH air setting. The system will remain in AUTO (controlling air speed, direction & temperature) regardless of the A/C button's status.

The MODE button will override the system's automatic control of airflow direction. When this button is used, the system will still automatically modulate air temperature and speed (providing automatic fanspeed managemen hat not been overridden by the FAN button, below). The AUTO light will no longer be lit. I find this button useful in the winter months. I will set it to floor/def in order to keep airflow coming out of both locations. The system will automatically modulate temperature.

The FAN butto will override the system's automatic control of air speed. When this button is used, the system will still automatically modulate air temperature and flow (providing automatic air flow management has not been overridden by the MODE button, above). Again, the AUTO light will no longer be lit. I find this button useful in the winter months as well. If the vehicle has more than two occupants, the windows are much more prone to fogging from the humidity generated through respiration. As the MODE button has already been used to direct air to the floor/def, I will kick up the fan speed in order to provide more airflow to the windshield and side windows. Again, the system will automatically modulate temperature.

The DEF button will do four things: (1) it will set the temperature to full heat output, (2) it will set all airflow to go through the defroster vents (both windshield and side windows), (3) it will turn the fanspeed to high and (4) it will command A/C compressor operation to ON. This will also override the "cold coolant" delay -- if the system is requesting heat to the interior and the coolant has not reached a certain predetermined temperature, the fan operation will be delayed. Pressing the DEF button will override that parameter, so even if the temperaure is set to full heat output, if the coolant is not warm enough, cold air will blow through the defroster vents at the highest fanspeed.

The fresh/recirc button will override the system's automatic control of where the air is pulled from: inside or outside the vehicle. Activating this button will keep all other settings the same, whether they are AUTOMATIC or one or more manual overrides have been commanded, above.

The :|: (microfilter) button will do the following: (1) command, at least, medium fanspeed (if it's lower, it will turn it up; higher and it will leave it alone), (2) command airflow through the dash vents; (3) command full recirculation (normally, airflow recirculation is limited to approximately 80%) and (4) command A/C compressor operation to ON. The system will maintain this setting for from 30 seconds up to three minutes, depending on ambient circumstances inside & outside the vehicle, then revert back to the preceeding settings.

I believe I've covered everything -- if not, let me know.

 

Yes you have it right Spenumatsa, you actually need to set the temperature after you push the auto button. If the car is cold the air will blow out at your feet, if the car warms past the set temperature it will come out of the dash vents. As you said you can override that with the mode switch. You can also control the fan but I never do I just let the system control that function. If you set the mode or the fan manually the temperature will still be maintained where you have set it. In fact the system will try to maintain that temperature even when it is off by letting warm or cool air enter through the floor vent or the dash vents.

If you need defrost you must push the defrost button to turn it on and then turn it off when you done with it. Actually you can push the Defrost button or select defrost/floor with the mode switch. As discussed previously the AC will run when you use defrost but the AC light will not come on.

The car warms up pretty quickly so you will have heat after a short distance.

 

Turning the temperature down will not make it warmer.

Just set it to AUTO and set the temp to a comfortable level, the system will maintain that temperature.

 

Thanks Chris..
One Question..What is the DEF button. I dont remember seeing it on the panel.

 

It's the middle button on the stack of three all the way on the right-hand side of the control panel (below the fan speed selector).