W211 Aircon Mystery
#1
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Dear Forum Members, I have a W211 with very low miles (60k miles). I love it and it's running perfectly, except for the air conditioner. When the aircon is working it blows ice cold, but it turns off and on and back off again, seemingly at random. And I mean it will turn on for thirty seconds, turn off for one or two minutes, turn back on again for 30 seconds, and so on and so forth. To be clear, what I mean by it turns off is the lights are on the dial like the air conditioner is on but if I put my hand in front of the vent there is no air coming out. Also, when it is on, it seems like the fan speed, no matter how high I put the setting, only goes up to about speed three and no higher, even if I set it to full-blast. Here in Thailand, where it's so hot, this is a big problem. I took it to the Benz dealer here and they said it was a loose connection and they fixed it, but alas the problem remains. The people at the Benz dealer here are extremely nice but it's a little difficult for me to communicate with them as I don't speak Thai. If anyone has encountered this issue and could give me some advice I would greatly appreciate it. Thanks sincerely, Jeff
#2
Member
The blower fan or it's thermostat resistor speed controller or both have likely stopped functioning properly. It is a common issue with 15+ yr. old MB vehicles. It's location is behind glove box, R&R is fiddly because bolts that hold it in are obscured from view unless you are able to contort your head & neck into footwell to look up & visualize alignment of torx bit w/ bolt heads. I replaced mine with a reman unit from FCPEuro just a couple months ago when it seized suddenly after doing as you describe for several months. They are out of stock on thermostat controller but in my case fan motor is what had given up so was able to recycle thermostat, replaced blower fan only & all is well again in 100+ F temps, ice cold a-c will set you free!
#3
Thank you!
Thanks so much for your reply, I appreciate it! You wouldn't happen to have the part numbers by any chance would you? That would help a lot as it's going to be a challenge to tell them to order a blower fan and it's thermostat resistor in Thai hahaha
Tha
The blower fan or it's thermostat resistor speed controller or both have likely stopped functioning properly. It is a common issue with 15+ yr. old MB vehicles. It's location is behind glove box, R&R is fiddly because bolts that hold it in are obscured from view unless you are able to contort your head & neck into footwell to look up & visualize alignment of torx bit w/ bolt heads. I replaced mine with a reman unit from FCPEuro just a couple months ago when it seized suddenly after doing as you describe for several months. They are out of stock on thermostat controller but in my case fan motor is what had given up so was able to recycle thermostat, replaced blower fan only & all is well again in 100+ F temps, ice cold a-c will set you free!
#4
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See attachments. Provide VIN for part #s.
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Jeff211 (07-21-2021)
#7
Super Member
I've noticed that when I go over bumps or small things on the road if my blower is at the lowest setting I hear squeaks. If I turn the blower fan up to the 2nd 3rd or higher notches on the screen, when I go over bumps it doesn't make that squeak noise. I'm wondering if my blower motor (12) years old is just wearing out. I looked online at FCP Euro and they have the blower motor for $140. Also have a resistor for another $100, but since the car gets cold/hot I don't think that needs to be replaced. I ran everything through STAR and I'm not getting any faults but the squeak is definitely annoying. The how instructions for replacing it is super easy! That's actually really nice. I was expecting something of a nightmare. Seems like a 20 minute job.
I'm wondering if a few drops of oil might help with the squeak. I know some don't recommend that because it would then just be a source for dust to collect and make the problem worse over time.
-Nigel
I'm wondering if a few drops of oil might help with the squeak. I know some don't recommend that because it would then just be a source for dust to collect and make the problem worse over time.
-Nigel
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#9
Super Member
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-Nigel
#10
Still not fixed, any ideas???
Dear Forum Members,
Thanks so much for your advice on my W211 aircon problem. It's been especially helpful for me because I'm a foreigner living in Thailand so there is a language barrier with the mechanics at the Mercedes store here. At this point, I've had the resistor and the fan replaced but the issue of the air conditioner going in and out still remains. One other interesting note is that the fan seems to have about 8 speeds as indicated by the red lights going around the fan speed indicator. No matter how high I turn it, it seems to only go up to about speed three. According to my not exactly professional translator, the mechanic said the things they did fixed it a "little bit" but to fix it completely the issue is "the box" which they said could be "very expensive" (around $3,000). I know this is a cryptic post but welcome to life as a 15 year old Benz owner in Thailand. I love the car and it barely has 60,000 miles so I'd love to keep it but wow do you need aircon out here in SE Asia... Well, the fact that I can't even change a spark plug (despite being raised by an amateur race car driver and tinkerer) doesn't help either. Any ideas from the MB geniuses on the forum what else needs to be done or what could be causing the aircon to still be going in and out and not at full and steady blast now that I've had the regulator and the fan changed? Thanks in advance for anyone's ideas, I really love the car and would like to keep it. Sincerely, Jeff
Thanks so much for your advice on my W211 aircon problem. It's been especially helpful for me because I'm a foreigner living in Thailand so there is a language barrier with the mechanics at the Mercedes store here. At this point, I've had the resistor and the fan replaced but the issue of the air conditioner going in and out still remains. One other interesting note is that the fan seems to have about 8 speeds as indicated by the red lights going around the fan speed indicator. No matter how high I turn it, it seems to only go up to about speed three. According to my not exactly professional translator, the mechanic said the things they did fixed it a "little bit" but to fix it completely the issue is "the box" which they said could be "very expensive" (around $3,000). I know this is a cryptic post but welcome to life as a 15 year old Benz owner in Thailand. I love the car and it barely has 60,000 miles so I'd love to keep it but wow do you need aircon out here in SE Asia... Well, the fact that I can't even change a spark plug (despite being raised by an amateur race car driver and tinkerer) doesn't help either. Any ideas from the MB geniuses on the forum what else needs to be done or what could be causing the aircon to still be going in and out and not at full and steady blast now that I've had the regulator and the fan changed? Thanks in advance for anyone's ideas, I really love the car and would like to keep it. Sincerely, Jeff
#11
Thanks for your reply
I bought an aircon last year, and I was using it just on trips. I cleaned it every three months. I never complained about it, and I was delighted. This year I can`t compare to the last, because the aircon is not working as well. The air it is blowing is very warm. A lot of people suggested me to clean it, but it is already cleaned. Probably it is defective because of the bacteria and dust. I used: https://www.socool.sg/ and they recommended me to buy another aircon. Since then I haven`t had any problem, and I am sure I won`t because this aircon is high quality.
#12
Member
Dear Forum Members,
Thanks so much for your advice on my W211 aircon problem. It's been especially helpful for me because I'm a foreigner living in Thailand so there is a language barrier with the mechanics at the Mercedes store here. At this point, I've had the resistor and the fan replaced but the issue of the air conditioner going in and out still remains. One other interesting note is that the fan seems to have about 8 speeds as indicated by the red lights going around the fan speed indicator. No matter how high I turn it, it seems to only go up to about speed three. According to my not exactly professional translator, the mechanic said the things they did fixed it a "little bit" but to fix it completely the issue is "the box" which they said could be "very expensive" (around $3,000). I know this is a cryptic post but welcome to life as a 15 year old Benz owner in Thailand. I love the car and it barely has 60,000 miles so I'd love to keep it but wow do you need aircon out here in SE Asia... Well, the fact that I can't even change a spark plug (despite being raised by an amateur race car driver and tinkerer) doesn't help either. Any ideas from the MB geniuses on the forum what else needs to be done or what could be causing the aircon to still be going in and out and not at full and steady blast now that I've had the regulator and the fan changed? Thanks in advance for anyone's ideas, I really love the car and would like to keep it. Sincerely, Jeff
Thanks so much for your advice on my W211 aircon problem. It's been especially helpful for me because I'm a foreigner living in Thailand so there is a language barrier with the mechanics at the Mercedes store here. At this point, I've had the resistor and the fan replaced but the issue of the air conditioner going in and out still remains. One other interesting note is that the fan seems to have about 8 speeds as indicated by the red lights going around the fan speed indicator. No matter how high I turn it, it seems to only go up to about speed three. According to my not exactly professional translator, the mechanic said the things they did fixed it a "little bit" but to fix it completely the issue is "the box" which they said could be "very expensive" (around $3,000). I know this is a cryptic post but welcome to life as a 15 year old Benz owner in Thailand. I love the car and it barely has 60,000 miles so I'd love to keep it but wow do you need aircon out here in SE Asia... Well, the fact that I can't even change a spark plug (despite being raised by an amateur race car driver and tinkerer) doesn't help either. Any ideas from the MB geniuses on the forum what else needs to be done or what could be causing the aircon to still be going in and out and not at full and steady blast now that I've had the regulator and the fan changed? Thanks in advance for anyone's ideas, I really love the car and would like to keep it. Sincerely, Jeff
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Jeff211 (10-29-2021)
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