Question about climate control function
09-14-2019, 11:29 AM
#1
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Thread Starter
Question about climate control function
I have an 05 E320 with the standard dual zone automatic climate control. I recently had an issue where the driver's side vent temp was about 10 degrees warmer than the passenger side. I evacuated the system, pulled a vacuum, and weighed in exactly 950 grams of virgin R134a and now that problem is fixed and the air is nice and cold from all vents, EXCEPT for the left rear vent in the center console. This vent still blows warmish air while all others blow cold with both zones set to 60 degrees. I have just been riding around with that one vent closed since I rarely carry passengers in the back anyway, but what could this be?
Also, my main question is this - How exactly does the climate control regulate the temperature? It seems that it will only blow ice cold air or hot air, and it regulates the temp with the fan speed. The problem is, at night especially the air coming out of the vents is uncomfortably cold even though it's blowing very slowly. If I raise the temperature up to a point where it starts to blow warm air, it increases the fan speed and heats up the cabin very quickly, so I'm stuck going back and forth between hot and cold on long trips.
Other cars I've owned with automatic climate control seemed to be able to regulate temperature by a combination of changing the fan speed and the temperature of the air coming out of the vents. Should my W211 do this as well, or are they designed differently? Thanks!
Also, my main question is this - How exactly does the climate control regulate the temperature? It seems that it will only blow ice cold air or hot air, and it regulates the temp with the fan speed. The problem is, at night especially the air coming out of the vents is uncomfortably cold even though it's blowing very slowly. If I raise the temperature up to a point where it starts to blow warm air, it increases the fan speed and heats up the cabin very quickly, so I'm stuck going back and forth between hot and cold on long trips.
Other cars I've owned with automatic climate control seemed to be able to regulate temperature by a combination of changing the fan speed and the temperature of the air coming out of the vents. Should my W211 do this as well, or are they designed differently? Thanks!
09-14-2019, 12:01 PM
#2
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1922 Ford Model T / no OBD
Do proper troubleshooting per thousands of topics on the forum.
With 4-zones you can read senor values on climatronic, but if you have scanner that might be better.
Your complain is common about moments of drastic changes. Unfortunately the program lacks slow adjusting settings, so when you enter very hot, or very cold car, it will blast at max till it gets to set temperatures and then stabilize.
My wife keeps changing the settings, but then she looses control what she wants, so I advise her to take the uncomfortable blast for few seconds and let the system do the job.
Adjusting the flow direction to the ceiling does good job.
With 4-zones you can read senor values on climatronic, but if you have scanner that might be better.
Your complain is common about moments of drastic changes. Unfortunately the program lacks slow adjusting settings, so when you enter very hot, or very cold car, it will blast at max till it gets to set temperatures and then stabilize.
My wife keeps changing the settings, but then she looses control what she wants, so I advise her to take the uncomfortable blast for few seconds and let the system do the job.
Adjusting the flow direction to the ceiling does good job.
09-14-2019, 12:08 PM
#3
Member
Thread Starter
Based on what I've read here I'm leaning towards a bad heater control valve causing the one vent in the rear to blow hot. I'm wondering if that could also have something to do with the inability of the car to meter in a little bit of warm air to help regulate the temp, or if it is doing what it was designed to do in that regard. From what you just said, I think the latter.
09-14-2019, 12:13 PM
#4
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1922 Ford Model T / no OBD
You have at least 8 sensors working on adjusting your system.
Do you feel lucky replacing them 1 by 1 without troubleshooting?
Do you feel lucky replacing them 1 by 1 without troubleshooting?
