sgr

Hello All,

My first post here, as I just got my car--an MY05 c230 sedan--1 week ago. Generally, I'm extremely happy; however, I'm having one problem that is pretty annoying. My car has the standard climate control system (i.e., two temp dials, and an "A/C" button rather than an "A/C off" button). When I turn on the "auto" mode, the fan NEVER drops below a speed of "3" (if manually set). This, when the outside temperature is between 55-62F and the internal temperatures are set at 68 - 72F. I've seen the fan run at higher speeds, but never lower, even after 30 minutes of driving.

Question: is this normal?? It's pretty annoying to constantly hear the roar of the fan, particularly at stop lights or in stop and go traffic.

Also, I've seen some posts that suggest that even when "auto" is turned off, the climate control system still maintains the internal temps, as per the temp dials. Is this true (the owners manual wasn't clear on this, at least not to me)? How is this possible if you have manual control of the A/C compressor?

Thanks, in advance, for your help!

Blake P

Hmmm...have you tried turning the music up?

sgr

Yep, turning up the stereo is my current strategy However, I wanted to see if this was a problem specifically with my car, necessitating a trip to the dealer. Also, I have no problems in running w/o the "auto" mode on, if it'll maintain the cabin temperature per the settings. However, the issue with the A/C compressor still confuses me, since pressing the a/c button appears to immediately turn on the compressor.

mick1

i didn't read the manual too much on air conditioning usage but my understanding is if you press auto, the air conditioner would run at its maximum power. if you don't want that, you should turn the knob manually and pick the setting you're most comfortable with.

MarkL

No, no, no. On "Auto", the system will attempt to reach the desired setting as quickly as possible. In extreme temperatures, this means a very high fan speed for a period of time. As the temperature in the cabin moderates, the fan will gradually move to slower speeds to maintain the temp while the air temp itself is automatically adjusted. In my experience with many vehicles with auto climate control, it's best to just let it "do it's thing" for the period it will run at high speeds. I leave my '02 C240 controls at 72 degrees almost all year round with good results. In "auto", the manual fan speed control and air distribution control knobs are disabled -- it doesn't matter where you move them (except moving the fan speed to "0" shuts down the whole system). If you press "auto" and the LED shuts off, you then have manual control of air distribution and fan speed, but NOT air temp directly. The system will still attempt to heat/cool the cabin according to ambient and selected temps. In general, I think when the cabin reaches the desired temp, my fan probably runs on 2 or 3 most of the time but I don't find it very loud.

Add: Oh, and as far as the system trying to maintain temps when "auto" mode is disabled, you can still have "AC on" with system in manual mode. AC (compressor) and auto/manual function are two independent functions. FWIW, whenever I turn AC off, I always switch to manual mode to prevent the fan from kicking up since it will never be able to cool the cabin with the compressor off.

lars

Not much left to say, but on my 03 the auto setting maintains a similarly annoying fan speed. Once the interior gets up to temperature at this time of year, it just cuts back on the heat but keeps the air volume high. I don't like listening to the fan and I have the radio off quite a lot. Most of the time I run with full manual control (auto off and ac off), which which still allows automatic control of the temperature. You can't turn temperature control off without shutting off the whole system.

BabyBenz6spd

Took me a about 30min to figure out how this "Automatic Climate Control" works.....

If you want Automatic Climate control:

Set Dial To "0" and just push "Auto" and the RED LED comes on. Then adjust the temperature on both **** to the desire temperature.
(This mean the A/C compressor will be ON to work with the Climate Control)

If you just ONLY the Heater to work on Automatic mode

Do the above and Push "A/C OFF" and now both Auto and A/C off LED are ON.
(In this situation, Outside temperature must be lower than INSIDE Vehicle Temperautre....or else it would not function properly)

If you want full Manual Mode

Set # Dial on Desire speed and make sure Both "Auto and A/C OFF" LED's are OFF

If you want Manual Mode without A/C working

Do the Above and and "A/C OFF" LED is ON


I am not sure what happens if you set the dials from 1 to "whatever" , and Push "Auto" (LED is ON) Is it on Auto or manual??

808_230K

i believe that's normal, mine does it as well. dealer told me that it tries to reach the set temp as quickly as possible, which means higher fan speed.

I'll hit auto and drop my windows when i get in the car, just to get all the hot air out, then use manual after the first couple of minutes...

sgr

First of all, thanks for all of the reponses! It sounds like my cars behavior is pretty normal, so I'll defer a trip to the dealer. MarkL, my experience with auto climate control systems is similar to yours: I tend to "set and forget", though previous systems tended to drop their fan speeds pretty quickly. With this car, I few minutes trying to better understand the manual mode some worthwhile.