2015W205C400

Hi everyone,


I recently picked up a 2015 C400. I noticed that the air coming out of the central vents on the dash are much cooler than air coming out of the side vents on the dash. Is this normal? Last night it was 40F outside and I had to turn the climate control to 78-80F inside the car to feel slightly warm air coming from the central vents. The side vents however felt at least 10degrees warmer. Is this normal?

DCDude1776@me.c

You might want to dig around in climate control screen to see how the vents are set. Mine were not set to Auto when I got the car with 17 miles on it. I never had an issue, but I did change the vents to Auto.

2015W205C400

Mine is set on Auto. I've also tried various manual settings and there's always a noticeable difference between the center vents and the side vents on the dash. The center vents always blows cooler air.

StanNH

Is the A/C button set to on or off?

2015W205C400

it's OFF

jkyriakou

Is the air volume coming out the same with the vents fully open?

StanNH

You can synchronize or unsynchronize both sides with that thing called "synch." Try it both with and without synch enabled, and see if that makes any difference.

2015W205C400

I've tried every combination possible and there is always a noticeable difference in temperature from the central vents on the dash. It's never as warm as the air coming out of the side vents. I'm going to do a more scientific test and borrow a laser thermostat from a friend to measure the actual temperature of air coming out of the vents when I get a chance later this week.

rapalax

I haven't noticed this but I have noticed that when the fan is set to level 5 or 6 (hard to tell when on AUTO but you can set it manually) there is a high pitched whistling sound coming from the windshield defog vents. The noise isn't THAT bad but sometimes its more noticeable. The noise goes away if I set it to the max or to the lower setting.

jkyriakou

Temp is perceived based on air velocity as well. If the air pressure seems the same then the issue lies in the heat exchanger perhaps. Most likely I'm thinking the central vents are siphoning to other areas (windscreen/floor). Have you been able to feel any air coming from those vents whilst it's on and set to the dash vents?

Mb747

Did you figure out a solution for this? I have the exact same problem and can't believe it was designed to behave this way. It keeps the car interior cooler than desired.

ManiacGT

If this is anything like BMW, their vents are independently controllable and temp differences are there so you can warm the cabin but keep cool air on your face.

twinpsark

I think I have something similar but stranger. The left side of the car is a lot cooler than the right side despite the fact that I adjusted the settings to low for both zones!

I sent the car to the dealer and they sent that the freon went low somehow! The car is only 500 km and a week old so its very annoying.

They claim that they revised the whole AC circuit and everything seems ok. Any suggestions ?

a02

Hi did you figure the solution my 2014 c class is doing the same thing for the past 3 days. I’m hoping there’s an easy fix.