Arm
Posts: 46
Joined: Tue Jan 07, 2020 5:53 pm

A vs M in Climate Control

Fri Oct 09, 2020 5:34 pm

I was reading up on the difference between modes on the climate control system and wanted to know what people's thoughts are between setting the recirculation modes....A, M, or no light on at all.

A mode, if illuminated, is supposed to detect external pollutants and automatically close off external air.

M mode, if illuminated, shuts off all outside air and is full recirculation mode until a sensor supposedly detects moisture that can cause fogging and turn A mode back on again.

Both lights off means full outside air at all times.

I've my suspicions that A mode just doesn't work because unless I have the mode set to M, I always detect and smell external odors be it exhaust fumes, smells from passing a restaurant, etc. So I'm not sure if there even is a sensor that detects external pollutants and such things.

Any thoughts?

eNate
Posts: 472
Joined: Mon Sep 09, 2019 5:33 pm

Re: A vs M in Climate Control

Fri Oct 09, 2020 8:11 pm

It's fairly easy to detect particulate above a certain size, but not odors. So that's my guess -- the car isn't "seeing" anything of concern, e.g. diesel particulate, dust, pollen.

I haven't changed my cabin air filter yet so I don't know if the i3 has a charcoal filter for odor filtration in addition to a particulate (HEPA type) filter.
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

Arm
Posts: 46
Joined: Tue Jan 07, 2020 5:53 pm

Re: A vs M in Climate Control

Fri Oct 09, 2020 10:23 pm

How often are you supposed to change it? The good ones seem quite expensive.

With the fires we had out here lately in So Cal, I'm tempted to do so even though I've had the car for less than a year.

eNate
Posts: 472
Joined: Mon Sep 09, 2019 5:33 pm

Re: A vs M in Climate Control

Sat Oct 10, 2020 9:40 am

According to the BMW maintenance guide, "Replace ventilation microfilter every 2 years based on the vehicle production date, or in connection with scheduled vehicle check."

But I've seen suggestions for 5,000 miles, 30,000 miles, and annually. With the pervasive wildfire smoke, I'd agree that changing it (or at least checking it) later this fall is a good idea.
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

Deutsch100
Posts: 102
Joined: Mon Sep 30, 2019 2:28 pm

Re: A vs M in Climate Control

Sat Oct 10, 2020 10:21 am

Living in So. California with wildfires and smog....I too think the filter should be changed more regularly, just like we do in our homes. Is there an easy way to get to the filter, w/o taking the car or dash apart? Thanks.
2020 i3S Rex; Capparis White

eNate
Posts: 472
Joined: Mon Sep 09, 2019 5:33 pm

Re: A vs M in Climate Control

Sat Oct 10, 2020 11:17 am

Deutsch100 wrote:
Sat Oct 10, 2020 10:21 am
... Is there an easy way to get to the filter, ...

I haven't changed mine yet, but YouTube is your friend.

https://youtu.be/0LNnvu3ibIo
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

Deutsch100
Posts: 102
Joined: Mon Sep 30, 2019 2:28 pm

Re: A vs M in Climate Control

Mon Oct 12, 2020 2:34 pm

Thanks eNate. Not too hard!
2020 i3S Rex; Capparis White

Arm
Posts: 46
Joined: Tue Jan 07, 2020 5:53 pm

Re: A vs M in Climate Control

Tue Oct 13, 2020 11:38 am

The OEM ones are Denso and are super expensive...$80 at the dealer.

trumpetdoug
Posts: 41
Joined: Tue Feb 04, 2020 8:46 am

Re: A vs M in Climate Control

Wed Oct 14, 2020 7:08 am

Is there a recommended place to purchase these filters outside a dealer? Might be up for doing this job myself.


Doug - out

eNate
Posts: 472
Joined: Mon Sep 09, 2019 5:33 pm

Re: A vs M in Climate Control

Wed Oct 14, 2020 2:56 pm

These are the ones I purchased. I won't vouch for them yet, but they're the same as Mini so there's a larger group of users out there than just us.

https://www.amazon.com/gp/product/B076C1HG1P
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

Return to “Technical BMW i3 Discussions”