AndyK

I used the Auto setting for the first time last night because it was kinda hot. I was using the manual A/C, with the center vents selected. Set the temp to 70, and got cool A/C. Fine. When I switched to Auto, the heat came on!? The temp setting was still at 70, and yet I still got warm air. Took it off Auto, and the A/C got cooler again.

This isn't a standard feature, is it??

rcg412

when you set the climate control to manual mode, despite the temp being displayed, it disregards it. Likely you cooled the car down to <70 degrees, and when you hit AUTO it either brought in outside air to warm up the cabin or kicked on the heat.

AndyK

Really? So Manual means the compressor goes till it explodes? Makes no sense to display the temp on manual then.
So, if I want the fan on a lower speed, it defaults to manual, and just gets colder and colder?

Ucube

Wait, that doesn't sound right. I live in Hot-ston, TX, and I've never used the auto mode. I always put my climate control on manual setting either A/C or heat. When I adjust the temp setting (with A/C on, for example), the air temp does change accordingly. I do this in my other cars with auto climate control as well. A temp setting of 70 with A/C on never gets too cold for me even after a long while. I thought the auto mode only kicks in the fan control to bring up or down the temp more quickly?

capt601

Did you try to lower the temp in Auto mode to say 66 or something and see what it would do? It may take a second or two to sense the temp, or maybe was the actual air temp below 70 degrees and it was trying to get the cabin temp to that temp by adding heat?

AndyK

I did try that, and the a/c did get cooler at 66. But why use the Auto mode at all if you can't control the fan speed or vent selection without going into manual?

1999Porsche911

If you manually change the fan speed, then why would you think you should be in AUTO? AUTO controls fan speed and temp. Changing the fan speed will not alter the car's heater/cooling output at all...just how fast the interior reaches the set temperture.

wwest

Wait..WAIT...

Some serious misunderstandings going on here.

The Porsche climate control has NO manual mode, as such.

Four of the system functions, fan speed, airflow outlet routing, inlet airflow source (fresh/recirculate) and A/C compressor operation, can be manually controlled, over-ridden, and any one of which will result in the "auto" icon being turned off. But ONLY the individual functions you actually change manually will drop out of automatic mode.

You can turn the compressor off and the system will still attempt to maintain your temperature setpoint, sometimes impossible, but...

There is yet another "manual" mode...and that is..

OFF...!

But even then if you did not first move the temperature setpoint to max cooling the mixing vane servomotor will remain in the last commanded reheat/remix position and as a result any "incidental" incoming airflow due to forward motion will be heated accordingly.

AndyK

So, like I thought, if you are in manual (or as Porsche calls it, Manuell) and you change the temp setting to 73, it will still reach 73 and stay at that temp, like it does in Auto. Or, if you are in Auto, and lower the fan speed, it will say Manual, but the temp setting will still be maintained--right?

I thought the slider switches on the 944 were confusing....!

1999Porsche911

Correct.

wwest

The way you describe the event is exactly, EXACTLY, how the system would react if you somehow selected defrost/defog/demist mode.

When you select defrost/defog/demist mode the system will ALWAYS assume you are doing that for good and sound reasons and will react by providing HEATED, VERY noticeably HEATED airflow to the windshield outflow ducts.

It might be the hottest day in the middle of summer but the system will still provide HEATED airflow in this mode, assuming the engine coolant is warm enough, of course.

But I wonder....

When you selected auto mode the system would typically open ALL three system airflow outlet paths, footwell, dash, AND windshield. It sounds as if just previously you had just the dash outlets selected.... and maybe..

RECIRCULATE..??

If so then the system would have most undoubtedly dropped out of recirculate mode and the instantaneous result would have been HOT, hotter, outside airflow entering the system rather than the cool(er) cabin interior airflow previously. It might take several minutes for the system to readjust the reheat/remix temperature modulation/control aspects in order to satisfactorily COOL that "new" HOTTER incoming airflow.

Additionally you would have felt the somewhat adverse effect from more than half of the system airflow being diverted to the footwell and windshield outlets.

Windshield outlets.....

With only the dash outlets having been used previously the interior windshield surface might have been quite warm, even HOT maybe. Now in automatic mode the airflow directed to the windshield will be heated slightly and then deflected, reflected, toward your face and upper body.

AndyK

On my Honda, I push the A/C button, and cold air comes out. Push "off", and no air comes out. Ahhh, the simplicity.

1999Porsche911

IF that is true, you have a problem with you Honda's climate control system.

lowside67

ZING!

AndyK

Well, not really. I just meant the Honda system is very intuitive.