Turn A/C Off When Knob Turned to Max...

Actually Max usually stands for recirc not A/C on....maybe this has changed over the years. My truck doesn't turn the recirc on when the knob is all the way to the left...and I'm glad because if it's cooler outside this wouldn't be the optimum setting.

The easiest thing for me to do would be to turn the knob all the way to the left (while keeping my eyes on the road) then pressing the button on as it gets warm then if it gets cool, pressing the button again...toggling it off and on. Toggling it on and off will save gas. If you turn the knob all the way to the left and the A/C comes on the you get cool so you turn it to the right a little the compressor will still be on and that will result in worse gas millage than toggling on and off. It's difficult to toggle because you have to press a button and turn a knob every time you toggle. I also think it is less safe to press a button and turn a knob since most people will look down at the knob to make sure they dont turn it too far to the right. Most people wouldn't look down if all they had to do was press the button to toggle on and off.

Maybe I would like to untie the knob and the button to allow more flexibility due to my anal tendencies (I'm a Mechanical/HVAC Engineer). Trust me I understand what goes into complicated systems.

The bottom line is when you have to press a button and turn a knob to get the A/C off, it's a bad design.

In the past few years, I've had several new cars and when Max A/C was on the recirc came on automatically but not the AC...that is an option. Max has always just turned the recirc on. However in my 09 taco it doesn't turn the recirc on instead it forces the A/C on.

Just seemed kinda weird to me.

 

Another answer to the too cold issue would be to leave the AC on and increase the temp until it's how you like it. It's not all or nothing.

 

You are correct...seems like this is the only option.


Thanks!

 

This is also correct but it does use more gas using this method. Toggling the A/C on and off will save gas vs. using the compressor at a higher temp.

 

Americans are so fat because of complicated A/C buttons

 

I noticed this feature on the newer highlander (had a rental while our older highlander was in the body shop). A/C came on automatically when you turned the temp dial to max cold. Anyone know what year they added this feature to the Taco? (FYI, that's probably why so many here didn't understand the problem, it wasn't like this on all our older models)

 

Max A/C Mode

• This mode eliminates the need for complicated operation by simply setting to the Max A/C mode position to operate the system at maximum cooling.

• When the Max A/C mode position is selected while the blower switch is on and the Mode Switch is in any mode other than DEF or FOOT/DEF mode, the A/C compressor automatically turns on even if the A/C switch is off, and the system is switched to the RECIRC mode. At this time, the A/C and RECIRC/FRESH indicators illuminate.

• FRESH mode can be selected by pressing the RECIRC/FRESH switch, even while in Max A/C mode.

• Airflow volume during Max A/C mode is adjusted by the position of the blower switch. However, if the blower switch is off, the A/C compressor does not turn on.

• Although the A/C compressor is always on during the Max A/C mode, pressing the A/C switch turns the A/C compressor off.

 

Very good!

 

This is not correct in my truck. How can it be always on but yet you can turn it off? I'm I missing something here?

 

There is another wrinkle to consider. Toyota added a UART to add logic to the defroster control. This will confuse you unless you know that when it happens it is by design.

Defroster control logic has been added to defog the window glass when the ambient temperature is low. Accordingly, input signals of the ambient temperature sensor and the vehicle speed have been added to the A/C amplifier.

Defroster Control Logic

• Due to the adoption of the defroster control logic, fogging of the windshield is minimized, improving visibility.

• The defroster control logic automatically changes the air inlet mode to the FRESH mode under any of the following conditions:

1. The DEF mode or FOOT/DEF mode is selected.
2. When the ambient temperature stays below 10°C (50°F) for 3 minutes or more during the RECIRC mode.
3. The ignition switch is turned on when the ambient temperature is 10°C (50°F) or less.

​

• Press and hold the FRESH/RECIRC switch for 2 seconds or more to turn off the RECIRC mode while the defroster control logic is operating.

 

Wow, I would think you could have figured this one out yourself.

Here ya go:

"Take your left foot (No, your other left foot.) and lift it off that footrest a little ways. There's a pedal by the left foot kick panel. You want to slowly press it down with your left foot (NO! Your OTHER left foot!!! Phew, that was a close one there!) until you reach the desired braking speed. Then let off and press it again to resume accelerating."

See, you never need to take your right foot off the accelerator. Hope this helps.

 

I am not certain. I tested it in my truck (2009), and when Max AC is selected on the blower switch I know the compressor turns on. Now, when I press the A/C switch, it appears to do nothing. If it does nothing while in this mode, than the literature I quoted was wrong.

An interesting test would be to activate Max A/C mode, press the A/C switch (we know the A/C light will say illuminated), and let it run for a while and see if the compressor does actually turn off. If it does turn off and the light stays illuminated then the literature will have failed by omitting this detail.

 

The compressor will not turn off in your test.

 

Okay. Then the only solution we have is to either not activate Max A/C mode, or to activate it, then back it off one notch and depress the A/C switch.

I'm with you, there are times I wish it didn't operate this way. Oh well.

 

I noticed the same thing awhile back, but was ashamed to say anything...thanks for bringing it up first! Just kidding of course; looked down and saw the light on and coulda sworn I'd turned it off... think I'll fiddle w/ mine, then maybe put a piece of tape over it if I start to freak...guess I'm too old school

 

Wow...I had no idea this a/c system was so complicated!

 

All we would have to do is untie the knob and the button......anyone care to try to figure out a mod for this?

 

I'm confused now... So I drove the truck on an errand during lunch, and I'm able to turn the A/C button on and off regardless of the position of the temperature gauge. Even when it's all the way to the right (cold). Is my truck super-special?

 

wtf

 

Through advanced mathematical computations and laser based measurments, I have determined that my left seat and instrument panel are .0037214 degrees out of alignment. Since it is to the left and taking into account the effect or phased array controls, it could explain why mine works just fine. The longer wire must have a knot in it that is reversing the effects of the control inputs.