I knwo there was some discussion earlier, but dont remember the conclusions. I noticed a whirring sound, when car is off, coming from the reading light/dome light/panorama roof control panel. What is it?

 

audiopilot microphone i think was the decieded resolution

althout it was rumored to be

1. climate control recirc feature
2. teleaid mic

greg

 

Not a recirc feature, but a small fan inside the vent which pulls air into the climate control sensor. Someone mentioned that if you place a very small piece of paper over the vent, it is held in place by the suction of the fan. I verified this. This fan seems to run all the time. I believe Richard followed up w/ some additional info. The TeleAid mike is the small round black circle above the rearview mirror arm.

 

MBTech verified that it was indeed part of the climate control, but he never got back to us as to why it ran after the car was shut off. I am wondering if it has something to do with the Rest button.

 

It wouldn't seem so, because I think the REST function simply blows whatever warm air is left after shutting off the ignition at a low speed. You can hear the coolant recirc pump come on, bu I'm not sure the climate control is actually functioning at that point. Also, they could link the activation of the sensor fan with the REST button since the REST function is probably off most of the time.

 

Richard put us wise to the console fan, as MarkL recaps.

My understanding is that REST function is not automatic. I've been driving my car with EC/REST engaged for several weeks. But when I turn the car off, the EC/REST climate control quits too. You have to manually push EC/REST to get REST function to begin. So, it doesn't seem to me that REST has anything to do with why the console fan "whirrs" all the time.

 

I know what you're saying, but should we clarify? I think the EC/REST button is actually dual-mode. That is, if you're driving around with it engaged, it's really EC (EConomy=no compressor). For the REST function, the engine must be off, and yes, it must be pressed again for each REST usage. They simply used one button instead of two since the functions are mutually exclusive (one w/ engine on, one w/ it off). I'm obviously not in my car now :o , but do I remember that the EC/REST button has two LEDs? Unless you press AUTO again, EC will remain engaged through ignition on/off cycles if you've chosen it. It's not like there's a separate "climate control" for EC/REST, those are just additional function selections.

 

Yes there are two leds one for each function.

 

Is the re-circular mode always on (as a default)?
I try the following and hope someone can give me some answers.
One day I drove my car (C320 02') and I wanted to use the EC/REST mode. And at the same time I wanted the fresh air (outside ) coming into my car. So I press the re-circular buttom and I saw a led (red) came on. However, for about maybe 20 or so minutes, I kenw that the re-circular buttom red led light is off by itself.
Now my question is how can I only wanted the outside air while using the EC mode? Or there is no way to set it on while using the EC mode. Thanks !!

 

I think you've got the recirculate functionality mixed up. When the recirculation is off (red light off), fresh air is entering your car. You turn on the recirculation (red light on) when you want to recirculate only inside air and prevent outside air from coming in. So, normally, it (and the red light) should be off. In the owner's manual it states that the recirculation mode will automatically turn off at different times in different conditions, so it is normal for the red light to go off after a period of time. Hope this helps.

PS...
The 2 main reasons you'd use the recirculation function is 1) for maximum cooling or heating -- this is because when you stop outside air from entering, it's easier to heat or cool the air "trapped" in the car; and 2) to keep "noxious" (bad) odors out of the car if you're following a diesel bus or something (or a skunk!).

 

MarkL,

Thanks a lot for your info and now it makes me more clear on how to use the recirculate functionality.