A/C starts up on "Auto"; never did before
 

After installing a TYC replacement Aux fan yesterday, I was outside adjusting the turn-on temperature for the other electric fan I installed earlier. I accidentally moved the dial and wasn't sure where I had it set before (I marked it well with a Sharpie this time).

I turned off the A/C to keep the Aux fan from running so I could set the adj. thermostatic switch, but noticed that I couldn't turn off the "auto" button. It hadn't been on full-time before, and when I had previously pushed it, it either was on or off.

I was pushing all the buttons previously, when I first had the A/C compressor fail to run a week ago, and might've pushed them a bit hard, so I possibly damaged the "auto" button.

Here's what the owners manual says about how to turn the "Auto" button off (but no mention about the "Auto" button acting as an on/off.

"You can cancel the AUTO program by selecting specific air distribution patterns for your personal comfort. You can direct air to flow onto the windows , toward the upper body , and into the footwell .
Temperature You can make individual temperature adjustments on the driver's side or the front passenger side. Your settings will be shown in the display 9. The displayed temperatures are reference values for the interior temperature. We recommend +72 7 (+22 6) as a comfortable setting, whether the air conditioner is operating or not. When you start the vehicle, this system ensures that the selected temperature is achieved as quickly as possible. It then maintains this temperature, regardless of the season.
Set the rotary dial 3 (refer to "Draft-free ventilation" on page 110) to a medium position to provide somewhat cooler air. This helps to promote driving without fatigue. Utilize this method of mixing air especially for making minor adjustments for personal comfort.
You can set uncontrolled heater output up to +90 7 (+32 6). Full cooling output is available from the air conditioner down to +60 7 (+16 6).< Online"

I have no problem with the way the button is supposed to work as it does now, but what changed the function from before?

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MAX A/C will also turn off "AUTO". It took me a while to figure how buttons worked. I'm still confused about the recirculation button. With in put from here, once it's cold I set it to the right light setting. I use fan speed to keep comfortable. If I let it at "Auto", I don't think it would reach 42F driving around town.

With a working fan, the CAN network probably has input to control temps and functions.

You might have something there; installing a (perfectly operational) new fan was the difference. Makes sense now. Thanks.



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You can leave the recirculation on auto (a light lit on button). The car will use recirculation when you first start with AC on to speed up the cooling and go to outside air after a few minutes.

I'm having mental block but I think there are two lights on the button. Left is auto right is recirculation and no loft is outside air.

I find when using auto climate and auto recirculation it just works no need to over ride. I use temp to adjust the fan speed rather than over ride the auto by changing the fan speed that way the fans just get quiet as the temp reaches the set temp.

AUC vs AUTO buttons
 

You must be confusing the AUTO button with the AUC button. The AUTO has only one light, and the AUC button has two.
Attachment 84322

A/C starts up on "Auto"; never did before
 

I'm talking about the auc button. Left light is auto recirculation.

I did mention "auto climate" and that's the other button

From the owners manual..

https://i.ibb.co/RYnQ1fr/ACC01.jpg
https://i.ibb.co/gyhnK2B/ACC02.jpg

I don't follow what's the problem if there is one. You can't set the auto off by pushing the auto button again. The auto setting goes off i you manually change air distribution or blower speed.

I did not know about the max ac button also doing that residual heat trick, that is pretty neat, thank you.

When I put the key in the climate control comes on, low temp, low fan, and with the AC on. I then have to hit the button to turn it off before starting the car. The E36 does the same thing,except that then turns it back on when I start the car, so I turn it off twice.

I would prefer it just to remain off. With my F30, I use the esys tool to do some FDL coding on the climate control module (IHKA) to behave the way I wanted. There was quite a bit of detail settings for it like that, what to do on startup etc. I would guess the climate control module and the e53 may have some similar coding, as is hinted by the thing above that the dealer is able to do. Anyone know anything about this or if there's coding for the climate control module?

A/C starts up on "Auto"; never did before
 

I coded my e70 and wife's F10 similar to what you want using bimmercode but that doesn't work on e53.

Wife's old e53 had "rest" instead of Max I had no idea that max does the same so that's a great tip