Redd

I know some people who would set their AC to "Blizzard Full Freeze" until the cabin temp was cool enough for them. And others who can't stand a big breeze, they'd just set it to blow "cooler" and wait. The thing with AUTO is that it is choosing fan speeds based on some random programmer's concept of "How cold should my beer be?"

A Brit might say 68F, but Heineken would say 45F. I wonder if the Germans make stout?

AFAIK no automaker allows for feedback to customize how the climate control system works, although some of the Audi's will remember the last? or preferred? setting for each key fob and switch that along with the seat and mirrors.

ex-quattro PETE

Random? The goal of Auto is to reach the desired interior temp as quickly as possible.

Redd

Since I have no idea how they changed the program in my "custom" modified climate control computer, I can't swear that mine is "normal" now. But it does not shoot the fan up to 12 and the air temp down to 55(?) when it is told to wake up and knock the cabin back to spring temperatures. It follows a more "deliberate" pace, more like blowing at 72F and a fan speed of 7. (Guestimating those, not reading anything off the display.)

It sets about making a "gentle but deliberate" cabin change, rather than a maximum effort. Which, in my limited knowledge, is something that wasn't affected by the new computer, whose purpose is to prevent evaporator ice-ups under extended runs, supposedly by shutting the compressor and allowing the fan to run until the evaporator fins are dry, the reverse of the usual sequence.

m1964

I had the moonroof tinted when we got the Q5 6 years ago, but I do not remember now what it was -it was supposed to be blocking some light but not most. There was a concern on this forum and at the installed that the moonroof can shutter if it absorbs too much heat so the installer was hesitant to use very dark tint.

Redd

Moonroofs have shattered for all sorts of reasons. Stresses in the glass or stresses from the frames can be invisible to the eye, and with added thermal stresses (heat or cold) one good bump on the road and they can shatter.

But I think the top tint manufacturers will warranty the entire installation, including potential damage caused by the tint. I can only say that there are a lot of us who have had brand-name tints applied by certified installers who have never seen them cause the glass to shatter.

The other alternative would be to have a mirrored tint applied, on the outside. Can't heat up the glass, and if it has to be replaced in five years, that's the price of being "sure". (These tints usually require heat and ammonia to release the adhesive, they won't just come up in water or rain.)

seakayaker7

My Q5's A/C was working fine until last month when I took a trip to the South Carolina Low Country with its high temps and high humidity. After about 2 hours in those conditions, the airflow dropped to almost nothing and the interior got quite warm. Adjusting the system manually had no affect. The next day everything was fine driving short distances around town. A few days later while driving home, the same problem occurred after approx 2 hours. I turned off the A/C and opened the windows to allow the cool 98 degree outside air to get inside. After 10 minutes I tried the A/C again and it was back to normal. I'm guessing the evaporator is icing up and blocking airflow, and guessing again that it's due to low refrigerant. Seems odd with only 16,000 miles but I'll get it checked at the next service.

Redd

"After about 2 hours in those conditions, the airflow dropped to almost nothing and the interior got quite warm"
See your Audi dealer. They should be aware that since last year, AoA has been aware of numerous complaints of the same type from customers driving in the SE and Texas in those exact circumstances. Your dealer will have to perform routine tests so you may need to drop your car off for a day.
But then, AoA can authorize replacement of the climate control computer. As of last year they were putting a "custom" computer in, apparently because they cannot simply field-update the existing ones.
The standard climate control computer shuts (or lowers) the cabin fan, and then shuts the compressor. Allowing an icy evaporator to get coated with a layer of ice crystals, which in high humidity become a solid layer of ice. That cuts off the air flow and the only "fix" at that point is to run the heater or park the car, until the ice has melted.
The new computer is supposed to shut the compressor (and perhaps generate some heat) but leave the fan blowing long enough and hard enough to de-ice the evaporator, preventing the problem.
The dealer told me that AoA had "dozens" of reports of this problem in the same extreme climate conditions, and that they were supplying new computers to all of them in an effort to see if that would fix it.
Personally I can't say if it does, I haven't been in the same situation since. (Hours at over 100F, followed by line squalls with 100% humidity.)

But no, you're not on drugs. Or if you are, they aren't the problem.(G) It really is a known issue and AoA HAS made some attempt at warranty repairs. Apparently they did not properly conduct environmental tests on the AC system.

m1964

I believe that low refrigerant agent charge can cause icing as well.

seakayaker7

Thank you Redd and m1964. I've made the same trip again without any problems, and I don't have problems driving around the Charlotte area. I'll have the refrigerant checked at the next service and inquire about the controller. Redd...does replacing the controller mean just R&R the module that's installed above the center console, or does it involve tearing apart the dash to get to it?

Redd

Low refrigerant, dirt in the system, there can be many reasons for problems. And even the best of long-experienced highly trained etcetera professionals have a hard time running some of them down. The Audi design failure is specific to these cars, finally known and acknowledged by Audi after one too many dealers said "You know, we've got this customer who insists..." and it apparently become way more than one customer. With the common key always being the weather pattern, i.e. blasting the AC for hours in high heat, followed by high humidity. With the problem going away the next day and not recurring in less extreme weather.
A difference of five degrees, or five percent humidity, that you'd never notice, is all it takes.
I have no idea what they replaced, only that the car was hidden away in the shop, and some special part from AoA's Custom Lab was put into it. One thing the elves are good at, is taking the car apart and putting it back together again without leaving fingerprints.(G) I'll give them credit for that. Usually an "A/C controller" is a computer board the size of a paperback book, but since these control dual controls, sunlight heat sensors, all kinds of things...If you've got custom "stuff" in your dash, just let them know.