Disable A/C compressor when front defrost is on?

That sounds like a problem that needs to be fixed, I've never experienced that.

 

It sounds as though water condensed from the cabin air is not draining out as it should. Try having the evaporator drain tube cleared out before doing something more drastic.

 

^ Once you've run A/C, to combat windshield fogging up, you will fog up when you switch it off. Likely the evaporator drain is functioning ok, it will still happen. It's just the nature of the beast, happens with any automotive A/C system.

The only recourse I've found when turning off A/C is to crack windows.

 

I agree with the opening of the window. In the old days when I was a youngin, the cars had "vent" windows on the front doors. If the windshield started fogging over, the first thing "Daddy" would do was to open those vent windows. He even turned them fully in which would blow the air from outside into the car and direct the air onto the inside of the windshield. It would keep the glass clear, and clear the condensation real fast. Back then you didn't have A/C in the cars. You were lucky if you had heat cause a lot of times the heater core's had rusted out and the hoses had been cut off and capped. Those were the "good ol" days.

Ron

 

Know exactly what your talking about Ron. In the UK we were years behind you in the US adopting aircon in cars mainly due to our cooler climate, but even back in the early 60's heaters were often offered as an extra to entry level vehicles.

 

My parents had a '58 Volkswagen with those, little triangular windows that rotated open about a vertical axis. Thanks, jogged my memory.

 

Fair enough.

It makes me wonder whether the OP is now using outside air at all? If he disables the compressor he'll have to use outside air continuously, otherwise all of the windows will fog up fast no matter how high he sets the temperature.

 

He said water "spews out", not condensation. That is not normal and I agree the drain tube is probably clogged - although if it were completely clogged you would end up with water in the front foot wells. Had that happen several times with a car I had last decade.

 

The design of turning on the AC compressor is to get rid of those moisture on the inside of windshield and your car did it right. However due to your asthma, yes it makes you suffer. You have to go to your dealer for the reprograming to shut off the AC compressor. Or you can shut it down by pressing the 'Temp" buttom of you MFD at the left side and touch the "A/C" on the display to turn it off everytime. For the water,moist... came out, as all said please check your water drainage when you go to your dealer. It' must be blocked by debries.

 

I missed Tekdeus' "spews out". Richard could be right about blocked drainage then.

OTOH, "spews out" could be hyperbole; he then says "fogs up".

Or maybe his car is possessed, a la Linda Blair??

 

So, with the A/C compressor not running, you are now allowing the system to use exterior air and not manually setting it to recirculated cabin air. True?

 

What I do is run the vents with the A/C on, but put the vent on the windscreen & footwell mode, then turn the heat right up & manually control the fan speed - try it. Might work for you. I'm a bit asthmatic as well, but not as bad as you I think.