24 GLS 450 A/C Fan Not Holding Set Speed
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24 GLS 450
24 GLS 450 A/C Fan Not Holding Set Speed
Hi there,
I'm having a problem with the air conditioning in my 24 GLS 450. When I set the fan speed manually to a high setting (like 6 or 7), it starts blowing at full blast but then keeps going up and down in speed erratically. I understand this behavior in automatic mode, but it's happening even when the fan is set to manual! I also double checked all the 3 zones to see if any one is set to automatic but they are all set to manual mode.
It's especially bothersome when the car is parked in the hot sun. I want to keep the fan on high, but it randomly drops down to speeds like 1 or 2, even though the display still shows it set to 6 or 7. The actual airflow feels more like what you'd get on settings 1 or 2.
I took the car to the dealership, and they saw it happening as well told me this is how it's designed. Their suggestion was to use automatic climate control, but that system switches to manual fan control when you adjust the desired temperature – which defeats the purpose of automatic mode in this situation.. But I don't get why the fan speed would change so much in manual mode.
Can any one with a 24 GLS 450 confirm if this is the same for them too?
I'm having a problem with the air conditioning in my 24 GLS 450. When I set the fan speed manually to a high setting (like 6 or 7), it starts blowing at full blast but then keeps going up and down in speed erratically. I understand this behavior in automatic mode, but it's happening even when the fan is set to manual! I also double checked all the 3 zones to see if any one is set to automatic but they are all set to manual mode.
It's especially bothersome when the car is parked in the hot sun. I want to keep the fan on high, but it randomly drops down to speeds like 1 or 2, even though the display still shows it set to 6 or 7. The actual airflow feels more like what you'd get on settings 1 or 2.
I took the car to the dealership, and they saw it happening as well told me this is how it's designed. Their suggestion was to use automatic climate control, but that system switches to manual fan control when you adjust the desired temperature – which defeats the purpose of automatic mode in this situation.. But I don't get why the fan speed would change so much in manual mode.
Can any one with a 24 GLS 450 confirm if this is the same for them too?
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
Can you describe what you mean by "manual fan control?"
I don't think there is one, if you have it on automatic.
There is a fan speed adjustment, but it only sets the basic parameter - A little faster or a little slower than "medium." A graphic shows the relative speed. It's still overridden by the temperature setting, which slows the fan when it approaches your set temperature.
The switch I'm talking about is the one directly to the left of the Auto switch.
When it's set on Auto, The temperature selection controls the fan speed.
A workaround is to set the temperature as low as it can possibly go. I think it will display "Min."
I don't think there is one, if you have it on automatic.
There is a fan speed adjustment, but it only sets the basic parameter - A little faster or a little slower than "medium." A graphic shows the relative speed. It's still overridden by the temperature setting, which slows the fan when it approaches your set temperature.
The switch I'm talking about is the one directly to the left of the Auto switch.
When it's set on Auto, The temperature selection controls the fan speed.
A workaround is to set the temperature as low as it can possibly go. I think it will display "Min."
Last edited by mikapen; Apr 15, 2024 at 03:48 PM.
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Hi there,
I'm having a problem with the air conditioning in my 24 GLS 450. When I set the fan speed manually to a high setting (like 6 or 7), it starts blowing at full blast but then keeps going up and down in speed erratically. I understand this behavior in automatic mode, but it's happening even when the fan is set to manual! I also double checked all the 3 zones to see if any one is set to automatic but they are all set to manual mode.
It's especially bothersome when the car is parked in the hot sun. I want to keep the fan on high, but it randomly drops down to speeds like 1 or 2, even though the display still shows it set to 6 or 7. The actual airflow feels more like what you'd get on settings 1 or 2.
I took the car to the dealership, and they saw it happening as well told me this is how it's designed. Their suggestion was to use automatic climate control, but that system switches to manual fan control when you adjust the desired temperature – which defeats the purpose of automatic mode in this situation.. But I don't get why the fan speed would change so much in manual mode.
Can any one with a 24 GLS 450 confirm if this is the same for them too?
I'm having a problem with the air conditioning in my 24 GLS 450. When I set the fan speed manually to a high setting (like 6 or 7), it starts blowing at full blast but then keeps going up and down in speed erratically. I understand this behavior in automatic mode, but it's happening even when the fan is set to manual! I also double checked all the 3 zones to see if any one is set to automatic but they are all set to manual mode.
It's especially bothersome when the car is parked in the hot sun. I want to keep the fan on high, but it randomly drops down to speeds like 1 or 2, even though the display still shows it set to 6 or 7. The actual airflow feels more like what you'd get on settings 1 or 2.
I took the car to the dealership, and they saw it happening as well told me this is how it's designed. Their suggestion was to use automatic climate control, but that system switches to manual fan control when you adjust the desired temperature – which defeats the purpose of automatic mode in this situation.. But I don't get why the fan speed would change so much in manual mode.
Can any one with a 24 GLS 450 confirm if this is the same for them too?
Also it will reduce speed automatically when taking a call or using voice control. But I've never had it change fan speed on its own besides that.
Comprehension is really not your strong point is it.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
I'll make it shorter for you.
I suggest you familiarize yourself with the cars.
SO, tell me where that manual button is - and explain how it can be primary when you have Auto mode selected.
It doesn't work that way. (Read my post or RTFM.)
Also, if your fan speed doesn't automatically adjust when it approaches the set temperature, or when you get in the car and it's extremely hot / cold when set on Auto, there's something wrong with your car.
SO, tell me where that manual button is - and explain how it can be primary when you have Auto mode selected.
It doesn't work that way. (Read my post or RTFM.)
Also, if your fan speed doesn't automatically adjust when it approaches the set temperature, or when you get in the car and it's extremely hot / cold when set on Auto, there's something wrong with your car.
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I'll make it shorter for you.
I suggest you familiarize yourself with the cars.
SO, tell me where that manual button is - and explain how it can be primary when you have Auto mode selected.
It doesn't work that way. (Read my post or RTFM.)
Also, if your fan speed doesn't automatically adjust when it approaches the set temperature, or when you get in the car and it's extremely hot / cold when set on Auto, there's something wrong with your car.
I suggest you familiarize yourself with the cars.
SO, tell me where that manual button is - and explain how it can be primary when you have Auto mode selected.
It doesn't work that way. (Read my post or RTFM.)
Also, if your fan speed doesn't automatically adjust when it approaches the set temperature, or when you get in the car and it's extremely hot / cold when set on Auto, there's something wrong with your car.
Last edited by darlop; Apr 15, 2024 at 10:06 PM.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
Read the first post.
He said the fan speed was changing automatically when it was set to manual.
I think he confused the buttons, but if he didn't, it indicates something is amiss.
Therefore I asked him which button he thought was the manual button. It's a troubleshooting question.
The manual button alters the basic fan speed, and the graphic will show various speeds, but it is overridden when Auto is selected.
New, and new-to-you cars can be complicated, especially if you head down the wrong path with some of the control functions.
Also, what the dealer said, or his interpretation of what the dealer said, was incorrect. Auto does not go into manual mode when you raise or lower the temp setting. (Unless you're not in Auto because you have activated Manual, which overrides the Auto mode.)
There are too many conflicting parts of the story. Needs clarification.
He could very well have a problem, but using the wrong buttons can also replicate his symptoms.
He said the fan speed was changing automatically when it was set to manual.
I think he confused the buttons, but if he didn't, it indicates something is amiss.
Therefore I asked him which button he thought was the manual button. It's a troubleshooting question.
The manual button alters the basic fan speed, and the graphic will show various speeds, but it is overridden when Auto is selected.
New, and new-to-you cars can be complicated, especially if you head down the wrong path with some of the control functions.
Also, what the dealer said, or his interpretation of what the dealer said, was incorrect. Auto does not go into manual mode when you raise or lower the temp setting. (Unless you're not in Auto because you have activated Manual, which overrides the Auto mode.)
There are too many conflicting parts of the story. Needs clarification.
He could very well have a problem, but using the wrong buttons can also replicate his symptoms.
Last edited by mikapen; Apr 16, 2024 at 02:03 AM.
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24 GLS 450
Hello,
My apologies for the confusion. To clarify, by "manual mode" I mean the climate control is not set to "Auto."
In "Auto" mode, you can still adjust fan speed using the dedicated Fan button left to the "Auto" button. I believe this is what the dealership was referring to.
@mikapen Also, what the dealer said, or his interpretation of what the dealer said, was incorrect. Auto does not go into manual mode when you raise or lower the temp setting. (Unless you're not in Auto because you have activated Manual, which overrides the Auto mode.) - You're right, I misunderstood the automatic climate control. I thought adjusting the fan speed in "Auto" mode would disengage the automatic function and switch to manual control. However, it appears the system allows fan speed adjustment while remaining in "Auto" mode.
However, even on the highest fan speed setting in "Auto," the airflow isn't as strong as setting the fan speed to 7 manually (without "Auto" on). - The core issue I'm experiencing is that the fan speed fluctuates when the climate control is not in "Auto" mode, even though I set a specific fan speed and the dealership is saying that it's by design, which I fail to understand on why would the fan speed change automatically when it's not on Auto?
@darlop That doesn't sound normal. But the fan strength can change depending on how many zones are active. Having every zone set to 7 sometimes makes them all work harder. But if you only turn on the front it won't be as strong at 7.
Also it will reduce speed automatically when taking a call or using voice control. But I've never had it change fan speed on its own besides that. -I understand that the fan speed might reduce momentarily for functions like phone calls. However, the issue I'm experiencing is a continuous, erratic fluctuation throughout normal driving. The display shows a constant speed (like 7), but the airflow noticeably drops and increases like it's switching between settings like 2 and 7 repeatedly.
My apologies for the confusion. To clarify, by "manual mode" I mean the climate control is not set to "Auto."
In "Auto" mode, you can still adjust fan speed using the dedicated Fan button left to the "Auto" button. I believe this is what the dealership was referring to.
@mikapen Also, what the dealer said, or his interpretation of what the dealer said, was incorrect. Auto does not go into manual mode when you raise or lower the temp setting. (Unless you're not in Auto because you have activated Manual, which overrides the Auto mode.) - You're right, I misunderstood the automatic climate control. I thought adjusting the fan speed in "Auto" mode would disengage the automatic function and switch to manual control. However, it appears the system allows fan speed adjustment while remaining in "Auto" mode.
However, even on the highest fan speed setting in "Auto," the airflow isn't as strong as setting the fan speed to 7 manually (without "Auto" on). - The core issue I'm experiencing is that the fan speed fluctuates when the climate control is not in "Auto" mode, even though I set a specific fan speed and the dealership is saying that it's by design, which I fail to understand on why would the fan speed change automatically when it's not on Auto?
@darlop That doesn't sound normal. But the fan strength can change depending on how many zones are active. Having every zone set to 7 sometimes makes them all work harder. But if you only turn on the front it won't be as strong at 7.
Also it will reduce speed automatically when taking a call or using voice control. But I've never had it change fan speed on its own besides that. -I understand that the fan speed might reduce momentarily for functions like phone calls. However, the issue I'm experiencing is a continuous, erratic fluctuation throughout normal driving. The display shows a constant speed (like 7), but the airflow noticeably drops and increases like it's switching between settings like 2 and 7 repeatedly.
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I understand that the fan speed might reduce momentarily for functions like phone calls. However, the issue I'm experiencing is a continuous, erratic fluctuation throughout normal driving. The display shows a constant speed (like 7), but the airflow noticeably drops and increases like it's switching between settings like 2 and 7 repeatedly.
The best case scenario is maybe the fan motor is bad and can't keep up. Otherwise if its a software issue then that's something only MB can handle.
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24 GLS 450
@rickth, can you check your build sheet to see if you have code 913 "Air conditioning preinstallation for hot countries"?
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24 GLS 450
Yeah like I said that's not normal and unfortunately the dealer gave your their standard reply of "that's how its designed". I guess you could try a different dealer or maybe an independent shop.
The best case scenario is maybe the fan motor is bad and can't keep up. Otherwise if its a software issue then that's something only MB can handle.
The best case scenario is maybe the fan motor is bad and can't keep up. Otherwise if its a software issue then that's something only MB can handle.
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2021 GLS580 | 2011 ML350 BlueTec | 2009 Pontiac G8 GXP
You did that. Is it switching between vent mode and recirculation mode?
Last edited by jkaetz; Apr 16, 2024 at 03:10 PM.
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'23 GLS450
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MBWorld Fanatic!
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
<<>>
I understand that the fan speed might reduce momentarily for functions like phone calls. However, the issue I'm experiencing is a continuous, erratic fluctuation throughout normal driving. The display shows a constant speed (like 7), but the airflow noticeably drops and increases like it's switching between settings like 2 and 7 repeatedly.
I understand that the fan speed might reduce momentarily for functions like phone calls. However, the issue I'm experiencing is a continuous, erratic fluctuation throughout normal driving. The display shows a constant speed (like 7), but the airflow noticeably drops and increases like it's switching between settings like 2 and 7 repeatedly.
The following was my Troubleshooting/ verification experience when I entered the car and it was 80°, and it was the same when it was 40:
I hit the Auto button once, which turns off Auto and the red light goes out.
Then I increased the fan speed to seven, with the temp setting at 72F.
The fan blew at that Max speed until it approached 72 - then the temperature at the outlets lowered, but the fan speed stayed the same.
Then I set the temp to 78, The fan stayed the same, temperature got hot.
The reverse: set the temperature really low, The temperature got cold but the fan still blew at 7.
Set the temp setting to 72, (fan still max), waited until It approached 72 and the outlet temperature reduced.
Then I hit Auto (Red light back on) and the fan immediately went to low. AKA normal.
My takeaway:
If all your experiences with erratic fan speeds came while your Auto indicator was off (no red indicator light), there is something wrong.
It looks like I'm verifying your most recent post. I just wanted to clarify what "off" meant to you. That's what it means to me.
Last edited by mikapen; Apr 22, 2024 at 04:54 PM.
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2024 Mercedes GLE 350
Yes, this is happening to me as well. I just purchased a 2024 GLE 350 and noticed the same issue. Took it in to Mercedes and they said it is normal. Funny enough, I didn’t have that problem while driving their loaner car.
Hi there,
I'm having a problem with the air conditioning in my 24 GLS 450. When I set the fan speed manually to a high setting (like 6 or 7), it starts blowing at full blast but then keeps going up and down in speed erratically. I understand this behavior in automatic mode, but it's happening even when the fan is set to manual! I also double checked all the 3 zones to see if any one is set to automatic but they are all set to manual mode.
It's especially bothersome when the car is parked in the hot sun. I want to keep the fan on high, but it randomly drops down to speeds like 1 or 2, even though the display still shows it set to 6 or 7. The actual airflow feels more like what you'd get on settings 1 or 2.
I took the car to the dealership, and they saw it happening as well told me this is how it's designed. Their suggestion was to use automatic climate control, but that system switches to manual fan control when you adjust the desired temperature – which defeats the purpose of automatic mode in this situation.. But I don't get why the fan speed would change so much in manual mode.
Can any one with a 24 GLS 450 confirm if this is the same for them too?
I'm having a problem with the air conditioning in my 24 GLS 450. When I set the fan speed manually to a high setting (like 6 or 7), it starts blowing at full blast but then keeps going up and down in speed erratically. I understand this behavior in automatic mode, but it's happening even when the fan is set to manual! I also double checked all the 3 zones to see if any one is set to automatic but they are all set to manual mode.
It's especially bothersome when the car is parked in the hot sun. I want to keep the fan on high, but it randomly drops down to speeds like 1 or 2, even though the display still shows it set to 6 or 7. The actual airflow feels more like what you'd get on settings 1 or 2.
I took the car to the dealership, and they saw it happening as well told me this is how it's designed. Their suggestion was to use automatic climate control, but that system switches to manual fan control when you adjust the desired temperature – which defeats the purpose of automatic mode in this situation.. But I don't get why the fan speed would change so much in manual mode.
Can any one with a 24 GLS 450 confirm if this is the same for them too?
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2024 GLS450 2017 GLS450 2013 GL350
ok I wonder if this is similar to the issue I've been having. I have a 24 GLS and when I have the air on with an intensity number selected and NOT on auto...after a short amount of time the air will completely cease blowing out of the front center 4 vents. The air will continue blowing out of the left driver and right passenger vents, but no air at all from the center 4. If i switch the air to a different intensity number, say from 5 to 6 its as if the air is woken up and then comes out the center 4 vents for a short while before it then again completely stops flowing and the cycle continues. I have dozens of videos showing this using a light napkin so you can see and hear when the air starts and stops with no changes to the system by myself. I have taken it to my local dealership 4 times now in southern CA and everytime they don't even try to figure it out, just say that there are no codes so we just updated the software and then they send me on my way. This last time I brought it in, they told me that if there are no codes, it means that the car is performing exactly as designed and there is nothing wrong. I showed them a bunch of my videos and also asked them if I experience the issue waiting in their parking lot, will they send a technician out to at least verify this is strange and not normal, and they said no. I am not really sure what to do if these dealerships refuse to do any oldschool diagnostics and will only plug in the computer.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
ok I wonder if this is similar to the issue I've been having. I have a 24 GLS and when I have the air on with an intensity number selected and NOT on auto...after a short amount of time the air will completely cease blowing out of the front center 4 vents. The air will continue blowing out of the left driver and right passenger vents, but no air at all from the center 4. If i switch the air to a different intensity number, say from 5 to 6 its as if the air is woken up and then comes out the center 4 vents for a short while before it then again completely stops flowing and the cycle continues. I have dozens of videos showing this using a light napkin so you can see and hear when the air starts and stops with no changes to the system by myself. I have taken it to my local dealership 4 times now in southern CA and everytime they don't even try to figure it out, just say that there are no codes so we just updated the software and then they send me on my way. This last time I brought it in, they told me that if there are no codes, it means that the car is performing exactly as designed and there is nothing wrong. I showed them a bunch of my videos and also asked them if I experience the issue waiting in their parking lot, will they send a technician out to at least verify this is strange and not normal, and they said no. I am not really sure what to do if these dealerships refuse to do any oldschool diagnostics and will only plug in the computer.
Did you ask if the Service Manager might sit with you for a better description of your issues. I've had good luck with that approach.
Does the Auto function not work?
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2024 GLS450 2017 GLS450 2013 GL350
Oh yeah, every time I go in I’ve made appointments. Bought the car July 24, and have been speaking with them about the same issue ever since then. Cars been in the shop 4 times already. Last trip which was picked up this week, they had my car for 10 days and said same thing. No codes = no problems and that they’ve done everything they can. I get home and check my dash cam and they only touched the car for 2 hours and their version of the test drive was under 2 minutes into a parking space. Obviously this is a dealership issue but the larger problem is this… are all these dealerships now adopting the model of it the computer shows no codes, they won’t repair? This was House Of Imports MB in southern CA btw.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
Oh yeah, every time I go in I’ve made appointments. Bought the car July 24, and have been speaking with them about the same issue ever since then. Cars been in the shop 4 times already. Last trip which was picked up this week, they had my car for 10 days and said same thing. No codes = no problems and that they’ve done everything they can
.....
.
.....
.
That's bad.
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2024 GLS450 2017 GLS450 2013 GL350
Yeah, they said I can just make another appointment, but when I do, they say they “couldn’t duplicate the problem or find any code.” It’s been a hassle but there have been multiple other issues with the car which all make me thing it’s connected either computer wise or electrical but again my advisor said that’s impossible because the car would show a code if that were the case.
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'21 AMG53 wDPP & ARC, 19 GLC300 - Former-03 C240,2 ML BlueTecs,20 GLE450 E-ABC,15 Cayenne D,17 Macan
Yeah, they said I can just make another appointment, but when I do, they say they “couldn’t duplicate the problem or find any code.” It’s been a hassle but there have been multiple other issues with the car which all make me thing it’s connected either computer wise or electrical but again my advisor said that’s impossible because the car would show a code if that were the case.
Did they not let you demonstrate your issue, with you operating, and a tech or the Service Manager on board to observe?
That would be a waste of everybody's time.
