[hoonose]

Hello All,

New member here with a question. I have just bought a 2016 535i with 22k miles. Just underneath the driver's side button that controls the temperature on the HVAC there's a small button. It doesn't push in when pressed and nothing happens on the system (that I notice). The button is there on the 5 series, the 3 series, and it's on a 2018 X2 "loaner" I'm driving while my car is in the shop.

I asked the service guy if he knew, and he didn't. So not being satisfied , I sought out the shop foreman with my question. He came over to my car, sat down, pushed the button a few times and said, "no, I don't know, never noticed it". I asked if it had something to do with "disassembly" if the unit was out of the car and he just shrugged his shoulders and walked away.

Not that I'm going to lose sleep over it, but does anyone know what's it for? Thanks for your thoughts.

[BigKutta]

That round dot like thing? Its a light sensor or something. Dont break it

[lsturbointeg]

That's the Flux Capacitor! It's what makes time travel possible

[wcr3d]

That is the camera so big brother can watch!
Sorry, please refer to BigKutta answer.

[EL Jeffe 5]

How about you put up some pictures of new ride before Questions JK
Look at @lsturbointeg for correct answer

[hoonose]

Thanks guys for taking time to reply. I enjoyed your responses. I was also told on another forum that it's a cabin temp sensor, close to what BigKutta was suggesting. Best to leave it alone, huh? Thanks again guys. As for posting pics, I can't because the dealer has had the car for the past two weeks.

[hoonose]

For some unexplained reason, I keep coming back to this thread to see if there are any replies. So far, Isturbointeg has the most comical and (possibly) most intriguing answer. Come on guys, "take the challenge". BTW, United BMW of Roswell, GA, did a great job on my car with another (and totally unrelated) issue regarding 'bad' front struts from the factory. Two weeks to get new struts, but now "perfect". The car rides and drives GREAT. I've got a 2 year old car with 23K miles and a brand new front end. WONDERFUL

[Kyngofpop]

That same black dot on Chrysler/Jeep vehicles is a laser that reads skin surface temperature and adjusts the climate control accordingly in conjunction with the sun load sensor and in vehicle temp sensor to make sure that the system doesn't blast you or under performs if your surface temp is or isn't inline with the climate controls pre-determined values.

ChryCo got this tech from their years with MB and I wouldn't be surprised if it performs the same function on BMW models. It's old news actually...kinda 04-05 ish if my memory serves me right.

My moms 05 AWD Hemi 300C has it and it performs especially well on a hot day hopping in the car after you've been swimming when the skin is at different temps than the climate system agrees with.

[andre.p.clarke@gmail.com]

I could do with a little help. I have just brought a 525d 2009 and am having problems with the climate control. I know how the change it thought the iDrive but ideally I’d like to change the temperature using the two knobs either side of the knob that controls the fan speed. Any advice is really appreciated.

[wcr3d]

Reading the manual might give you a better idea on how the system works.

[lsturbointeg]

Originally Posted by Kyngofpop

That same black dot on Chrysler/Jeep vehicles is a laser that reads skin surface temperature and adjusts the climate control accordingly in conjunction with the sun load sensor and in vehicle temp sensor to make sure that the system doesn't blast you or under performs if your surface temp is or isn't inline with the climate controls pre-determined values.

ChryCo got this tech from their years with MB and I wouldn't be surprised if it performs the same function on BMW models. It's old news actually...kinda 04-05 ish if my memory serves me right.

My moms 05 AWD Hemi 300C has it and it performs especially well on a hot day hopping in the car after you've been swimming when the skin is at different temps than the climate system agrees with.

Ha! Are you being funny or smart cause I wasn't sure if you're being serious or not lol!

[ezaircon4jc]

On the subject, does anyone know just where the interior sensor is physically located? I've been all over newtis and it just explains function, not actual sensor location (that I can find).

TIA

[wcr3d]

I'm pretty sure it is in the passenger side air duct.

[ezaircon4jc]

Originally Posted by wcr3d

I'm pretty sure it is in the passenger side air duct.

Center or nearest the door?

And... THANKS!

[wcr3d]

Deeper inside, my understanding it is before that side splits to center and outside.
What I read was saying it was easier to get to from the wheel skirt.

[Qsilver7]

KoP was correct...its a temp sensor. The answer to the original question is...the "dot" (little black button) is the temp sensor for regulating the IHKA. In the past, there used to be a "forced air" set-up...so there was a grid (#17 in the 1st pic below) where air was drawn into the IHKA across a thermistor or other sensor which helped the IHKA control panel maintain the set temperature. But from July/2012 BMW changed to the little "dot/button" thingy. This change also reduced some of the common issues with the forced air induction set-up...which was the accumulation of dust on the little fan blades (inside the IHKA) as well as the noise that occurred as the interior fan became imbalanced due to the dust build up.

[ezaircon4jc]

Originally Posted by Qsilver7

KoP was correct...its a temp sensor. The answer to the original question is...the "dot" (little black button) is the temp sensor for regulating the IHKA. In the past, there used to be a "forced air" set-up...so there was a grid (#17 in the 1st pic below) where air was drawn into the IHKA across a thermistor or other sensor which helped the IHKA control panel maintain the set temperature. But from July/2012 BMW changed to the little "dot/button" thingy. This change also reduced some of the common issues with the forced air induction set-up...which was the accumulation of dust on the little fan blades (inside the IHKA) as well as the noise that occurred as the interior fan became imbalanced due to the dust build up.

I ask as I'm having cooling issues; sporadically the min temp out of the vents is around 51º. The only way to get colder air is to select 60º and rotate the wheel all the way to blue (normally the HVAC is set to 68º and the wheel is pretty much in the middle). After a while the air seems to stabilize back where I set it. It's been at the dealer and they found the system about .3# low on refrigerant. The problem is it happens so sporadically they can't replicate it consistently. They did put dye in the system to check for a leak. I figured I'd just replace interior sensor (if it's easily accessible) and go from there.

They also replaced the high pressure fuel pump (P/N 13 51 8 604 231) per a TSE.

[Kyngofpop]

Originally Posted by lsturbointeg

Ha! Are you being funny or smart cause I wasn't sure if you're being serious or not lol!

I was being serious...for once lol