Brittnie Jane

So, it's been pretty cold here in Louisiana and I've noticed that when I have the air set to let's say 80 (bc that's what I had it set to this morning) my vents blow hot and cold air out, not only that, it will switch up which vent(s) are blowing hot and cold air. It does this with a/c set to off and also on.
I will feel warm air then all of a sudden I get hit with cold air or one or two vents will start blowing cold air and one or two warm air.
Is this normal for this model and year or is something wrong?

guhvies

If the car has warmed up, it should only blow hot air. If it hasn't warmed up and it is cold outside, it will start cold and then slowly heat up.
I would try warming the car up first to say 80F then put the air on. If after a minute it is blowing hot and cold air, a visit to the dealership is
in order.

HTH

Brittnie Jane

I took it to the dealer, the tech stated that he felt the air doing as I explained. He ran a diagnostics test and it came back normal. He stated that everything was nornal, it's just the car trying to balance the temperature, "The air system has a lot of flaps that open and close."
I just don't agree that this is normal, 80 should blow 80 consistently.
Also, he also stated, "Try changing the settings to just dash vents and not floor and dash or defrost and dash vents." I've tried all of that for one, two, I shouldn't have to do that not run my defrost to keep the heat consistent.

teksurv

I don't think this part is actually correct. If set to 80 degrees, it represents running warm or cool air to maintain 80 degrees in the cabin, not the temp of the air coming out of the vents.

Tirgoman

Do have the controls set to Auto? It should decide where, the temp how much sir is delivered. I think something is out of wack, maybe a sensor or blend door control. The temp you set is the temp that the system is trying to keep, not the temp of the air coming out the vents but it shouldn't vary line you're describing.

BlankProc

This is the truth. If I were you @Brittnie Jane I would take it to another dealer for a second opinion- if that's possible. I have a 2019 C coupe as well and have been nothing but impressed with the climate control, mine actually leans a little bit on the warm side for me. (But everyone's temp perception/feel is different, which makes it tough to judge.)

Brittnie Jane

I tried auto and it still occurred

Brittnie Jane

We have three dealers in my area, New Orleans Baton Rouge and Covington (Where I bought mine and took it) so definitely an option. We also have a few import garages locally.

it definitely gets warm, but suddenly being hit with cold air kinda sucks lol

Brittnie Jane

So, are you saying that what I'm experiencing is normal? I've never had a vehicle do this, my CLA would blow warm air if it was set to 80 or any other warm temp until I set it lower

BlankProc

What you're experiencing sounds abnormal - but it is normal for the climate control system to adjust between cool and warm air depending on the actual temperature in the vehicle. It is true that just because the climate control is set to 80, it doesn't mean the air is blowing up to 80 degrees - it means it is blowing out hot air to raise the temp to 80 degrees inside the car. I've never owned a CLA so don't know the specifics of that system but I'd imagine it's comparable.

Bottom line is if you're cranking it to 80, and cold air starts coming out before the car is actually 80 degrees (or close) inside, there's probably something wrong. MBs are not immune to irregularities - the E class I just turned in for the C coupe used to randomly blow out heat for about 5 seconds in the middle of GA summers. There's some threads around Benz forums on that issue, although it was never a big deal.

In most MBs, I just turn it to auto until it gets to a reasonable temp, then turn auto off and fine tune. If you can't just do that and have it work - I'd take it to the dealer that would fix it.

Tirgoman

Money is right. The only thing I would add is that in Auto Mode, the air will come out of the appropriate vents. For A/C this would normally be the dash vents. For Heat it would be the floor vents. There are times where it blends the 2. A little air always seems to come out of those small vents on top of the dash that blow air onto the front of the side windows. In heat there is also always a little air that comes out of the top defroster vents. But if you put it in defrost all the air comes out those vents. What you originally described is not the way it should work so you've got an issue. You could try the manual dial to direct air to the dash or both or floor vents and see if at least the air comes out from where it should. There is a small return vent on the dash, don't remember where on what car that sucks in the air from the car to measure the temperature in the car. The goal of the Auto system is to get the interior temperature to what you set it at so in A/C for example the air coming out might be 55 degrees trying to get the car to 72 degrees. A sensor could be bad, a blend door bad, a computer black box bad, lots of things, but it's not normal.

Brittnie Jane

Thanks ya 'll. When it cools off again here I will play around with the settings some more and see what happens. I will take it for scheduled service if it happens again. Y'all it's February and it's 80 degrees and humid...Gross


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Brittnie Jane

Just a little update, I will be taking my car in for service this Wednesday. A few days ago I tried to use the heat and it was cold, no matter what I did it would only blow cold/cool air. It was not very cold out this particular day, however, I had been at work and was freezing from the a/c.
It really seems like the outside temperature is affecting the heat and cooling system. It's like, it's warm out you don't need heat today! Today it is chilly out and the heat is working fine as of this morning.

Brittnie Jane

I brought the car in yesterday at 7:00am, they called me to come back at 1:00pm, they could not replicate the issue(s). I was yet again so aggravated that they could not find the issue. We got in it and I drove it around with my actual salesman and the a/c heat system immediately started malfunctioning, he was like, "Oh, okay, it's definitely not supposed to be doing this. Something is definitely wrong.

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Brittnie Jane

My salesman and I drove it and got it to replicate the issues, they are ordering a new control panel.
Also, now my passenger side window has decided to malfunction and stop working off and on. Ughh!

C280 Sport

What about just turning the temp up to high? Does it blow warm? The system has a climate temp sensor on it that helps regulate the air temp otherwise it will just blow hot the entire time.

C280 Sport

It should be under warranty so no worries. Drop the car off and they give you a loaner anyways.

Brittnie Jane

We tried high and 66 on one side and the temps felt the same.
Yep, it will be going in. Just sucks, it's only a month old. Still has the plastic wrap on some parts.

Tonymeza55

Hi, any update if replacing the control panel helped with this? I have the same issue. I set both sides on hot and driver side will blow cold and passenger hot.

Thanks!

addio06

While we haven't had to use heating in SoCal, I did previously have an issue with my air conditioning. It would be set to AC Auto and a temperature such as 72 but the fan would not blow even after several minutes even though it was clearly hotter than 72 in the car. I tried pushing the "bigger fan" button and making it blow but it would not work.

The workaround I found until it was fixed by the dealer with a software update was to click "Auto" to turn it off and then to click "Auto" again to turn it back on. The system worked after that. So it may be a software issue.