How do I use the heating and AC function?
 

Dear all, I've never been able to really use the heating and AC function as the way they should in my 2009 Audi A4 B8 model. I have the base model so it's not dual climate. I don't understand why the AC button always turns on, how to use the "auto" function. I wish the system was a bit more intuitive.

if you run the AC it will produce "dryer" air, on the other hand hit "auto" ,set your temperature and go.

It's pretty much like the HVAC in any other car... there are controls for the fan, the temperature, which outlets the air is discharged through, and whether or not the AC compressor is enabled. Selecting Auto will caust it to automatically determine where to discharge the air, and what speed to run the fan at. It will also enable the compressor if it's not enabled. You can leave the compressor enabled all the time if you like, it will still modulate the temperature as needed, though I personally manually turn it off unless I need cooling or dehumidifying, simply because I think it's wasteful. You can also override where the air is discharged and/or what the fan speed is, though pressing auto will revert those back to auto control.

I generally just leave it on auto, and only intervene with turning the AC on/off when I want it.

Ever since the 'Auto' function came on in my Summer weather hot as hell car and cracked my windshield I've manually controlled the climate control.

Auto is a 'set it and forget it' type of control. You should try it out to see if it fits your needs.

1) Don't use Auto.
2) Just adjust the vent setting to bring out air where you want it.
3) Adjust the temperature by turning the knob.
4) Adjust the fan speed, and it will automatically scale up/down as need be -- according to the temperature you picked.
5) Don't use Auto.

Why would you say that? I almost always use AUTO and just set the temperature to 74. Then you just don't need to think about the temperature of the car ever again.

My car is temperamental with Auto. In summer if I set my temp to 66F with AC on, the car will reach 66F, and then cut the Fan Speed to 1, or worse turn off the windshield air vents. A few minutes later I notice I'm sweating and my eyes are burning. As the car heats up, it'll douse me with a ton of cold air to bring the temperature back down.

Same way in winter. If I set it on Auto and 70F. The car will send in hot air until the car is 70F, and if it happens to get over 70F, it'll throw in a bit of pure COLD outside air until it's back to 70F.

I prefer a nice steady airflow. Which isn't even possible in the non-Auto mode because the car still screws with the fan speed as the cabin temperature changes.

Strange, mine doesn't behave like that at all.

mine isn't like that at all either. set it at 70-72 for the winter and mid 60's for summer all on auto and never had a problem, unless the wife starts pushing buttons.

Mine is on Auto 99% of the time and works exactly the way I want it to. With the B8, the performance is back to the standard set by the B5. They both work seamlessly.

Both B6s I owned (and every one I rode in) as well as the B7 behaved horribly. I ran them manually all the time. The main problems were the lack of responsiveness to my changing the temp as well as it ramping down fan speed way too soon. When it was hot as hell outside, I would set it on 65 and when it was still baking inside, it would start slowing down. I used to yell at it "In what alternate universe is it even close to cool in here??" lol. EVERY one I drove did this.

Anything the a/c could possibly do would never cause a windshield crack. Extreme heat can cause a stone chip to spread into a crack, but that's all.