Max AC Come on Automatically?

2014 DCLB: long freeway driving on a very hot day (97+ degree), I notice very ocassionally the Max AC light will illuminate for varying lengths of time and then go out. Is there an internal sensor to assist the standard cooling, or as I am towing could a hard hill climb draw down the vacuum enough to close a bypass door, or something. All seems to cool OK.
Thanks.

 

Not sure what the max ac light is?

My 14 if I switch it to max ac on the dial, the ac light and the recirc light comes on

Is there another?

 

Did you have it in the defrost mode by chance?

 

Thanks, I meant the Recirc Light, thinking that it meant the same as if the switch were in the Max AC positiin.

 

No, either dash vents or dash/floor.

 

Max air simply means that air from outside is being draw into the evaporator coil to be cooled. It's meant to be used when first cooling off the interior when the vehicle has been sitting in the sun, the outside air even though hot will be cooler than the interior air. So my guess is that periodically the 'puter tells the ventilation system to air some fresh air to the cabin to dilute the possible beer farts and or body oder and add some O2 to stave off the sleepys caused by higher CO2 levels.

Calling it "max air" makes as much sense to me as clicking on "start" to turn off your 'puter.

 

Wut?

 

Put down the crack pipe!

 

Now I understand

 

I always thought max ac meant it turns the ac on and the recirc at the same time because pushing both buttons it too hard and I want heated effing mirrors

 

It does, and me too.

 

True & I apologize for miswording the title, but is there a sensor that periodically activates the recirc? Driving along in normal that light will very occassionally illuminate without pushing the recirc button.

 

you have it backwards.....

 

I'll stick with my statement with the qualification that that's how it works for some of the vehicles I have had but since there is no industry standard for what "MAX A/C" means your vehicle may be different. My 07 Tacoma does not have a max ac selection.

 

Never have I once seen a vehicle with max a/c option do anything but switch to recirc. It would just make no sense at all, if it didn't.

 

From the manual regarding MAX A/C: For quick cooling, turn the temperature control dial to the MAX A/C position. The air conditioning will automatically turn on and the air intake selector will be set to recirculated air mode.

Going back to OP's original question, answer is also in the manual:

■ If the ambient temperature drops while using the recirculated
air mode:

The air intake mode automatically changes from recirculated air
mode to outside air mode after a few minutes.

To cancel this function:
Press and hold (recirc button) for longer than 2 seconds.
To reactivate this function:
Turn the engine switch to the LOCK or ACC position

Attached the page as a pdf so you can see it. Really wish I could smoke whatever miniceptor is on, but he probably has to free base that shit!

 

Thanks ! did not know that!

 

That is probably the circuit that derped. Mine was on outside air and automatically switched to recirc (inside air), but only happened a couple of times and very briefly.

 

If it has ac it does.