intermittent AC problem benz has a mind of her own
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Newbie
Joined: Sep 2016
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2002 S500 ,2008 GL 550, 2009 c300
intermittent AC problem benz has a mind of her own
Have a 2008 gl 550 with an intermittent AC problem. All climate controls and functionswork but the problem is that the system seems to decide on its own when to produce cold air and when not too. In general, when the car starts it'll produce nice cold air but when moving it may or may not put out cold air. Usually the change is is preceded by something in the vent system moving, then a stale odor. cab air filters are clean.
Super Member
Joined: Jan 2007
Posts: 622
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From: CA
11 ML550, 95 Supra TT, 14 Audi S4
I've had the same problem with mine since the compressor was replaced (by a MB dealer). The dealer has reflashed the control unit, checked pressures, and evacuated and refilled the refrigerant without a cure.
On my car, it seems to be much more likely to occur on 100F+ days with the A/C on max. I've found that if I don't let the car set the fan speed to maximum and knock the fan speed down, it is a lot less likely to happen although that's annoying because you can't take advantage of a really effective A/C system on the days you want to use it the most. It works fine on cooler days.
On my car, it seems to be much more likely to occur on 100F+ days with the A/C on max. I've found that if I don't let the car set the fan speed to maximum and knock the fan speed down, it is a lot less likely to happen although that's annoying because you can't take advantage of a really effective A/C system on the days you want to use it the most. It works fine on cooler days.
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Newbie
Joined: Sep 2016
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2002 S500 ,2008 GL 550, 2009 c300
Thanks for the reply. All pressure is correct. to reiterate, it will blow cold, then some noise will happen in the dash, then it will blow hot. almost like the heater core is activated. then after a while, it will return to blowing cold. when you noise is heard, a wet leather smell comes out the vent for a half a minute.
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Joined: May 2015
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From: Allentown, PA
'08 GL 320 CDI
Hmmmm. That one is above my pay grade. Maybe the electronic control is going wonky? Or a sensor? I know... just guessing there isn't very helpful. I wonder if it was hooked up to computer (STAR/DAS) if the coputer could see what is going on. Might be worth an hour or so of diagnostic time to find out exactly what's happening.
Heater cores can get dirty and musty/moldy - the fins - so when air blows over it, it sometimes gives off a musty/old smell. Maybe that explains the smell?
Heater cores can get dirty and musty/moldy - the fins - so when air blows over it, it sometimes gives off a musty/old smell. Maybe that explains the smell?
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Joined: Apr 2017
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1999 E240, 2007 GL500, 2004 Suburban Z71, 1997 Ford Escort MK7, 1979 VW Beetle
I had a problem like that in my GL500, the AC gas was low and I found 3 micro holes in the rear evaporator core and 5 micro holes in the front condenser. To find where the gas is leaking is necessary a lot of patience and work, if you do not have a professional equipment to verify where the gas is leaking I recommend you to take your car to a professional.
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Joined: Jul 2016
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From: Savannah, GA
2008 GL450, 2002 CLK 320 (gone)
I am having the same issue with my 08 GL450. It started out as a very occasional issue, but is now a "more-often-than-not" problem. My indy has recharged the system, replaced the low-pressure hose per an MB Service Bulletin, and verified operation of the compressor to be normal. No fault codes were present. He suggested that the issue may be in the electronic temperature controls which are part of the COMMAND system, and basically said the car needs to go to a dealer. With 180k on the odometer, I'm not sure I'm willing to invest a couple grand more in the car.
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Joined: Jan 2007
Posts: 622
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From: CA
11 ML550, 95 Supra TT, 14 Audi S4
We had a ~100F day yesterday and as soon as I switched the A/C to auto, the compressor kicked off. Cycling the A/C button on and off, which sometimes will get the compressor going again didn't work, but pulling over, restarting the car with the fan speed dialed back slightly got it going again and it worked for the rest of the ~ 2 hr. trip. Still no idea what the problem is, but allowing the system go to "max A/C" mode on a hot day is just about guaranteed to make the compressor kick off on my car.
I'm also done paying the dealer to try to figure it out on a vehicle with almost 200K miles. I'll just live with having to manually control it to make it work.
I'm also done paying the dealer to try to figure it out on a vehicle with almost 200K miles. I'll just live with having to manually control it to make it work.
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Member
Joined: Jul 2010
Posts: 131
Likes: 24
gl550
I've had the same problem with mine since the compressor was replaced (by a MB dealer). The dealer has reflashed the control unit, checked pressures, and evacuated and refilled the refrigerant without a cure.
On my car, it seems to be much more likely to occur on 100F+ days with the A/C on max. I've found that if I don't let the car set the fan speed to maximum and knock the fan speed down, it is a lot less likely to happen although that's annoying because you can't take advantage of a really effective A/C system on the days you want to use it the most. It works fine on cooler days.
On my car, it seems to be much more likely to occur on 100F+ days with the A/C on max. I've found that if I don't let the car set the fan speed to maximum and knock the fan speed down, it is a lot less likely to happen although that's annoying because you can't take advantage of a really effective A/C system on the days you want to use it the most. It works fine on cooler days.
Super Member
Joined: Jan 2007
Posts: 622
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From: CA
11 ML550, 95 Supra TT, 14 Audi S4
Member
Joined: Jul 2010
Posts: 131
Likes: 24
gl550
Member
Joined: Jul 2010
Posts: 131
Likes: 24
gl550
I have gl550, 2010, the AC has been working ON and OFF at cooler days before
1/ Now it works only when leaving the car overnight,
2/ But, AC works ice cold at 1st time ON Only, if turning Off and On again, it will not work.
Checked without error code. ( pressure 5 bar when running ice cold, 8.5–9 bar when not)
Tried adding diode but no help
Any ideas!!!
1/ Now it works only when leaving the car overnight,
2/ But, AC works ice cold at 1st time ON Only, if turning Off and On again, it will not work.
Checked without error code. ( pressure 5 bar when running ice cold, 8.5–9 bar when not)
Tried adding diode but no help
Any ideas!!!
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
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From: Allentown, PA
'08 GL 320 CDI
I have gl550, 2010, the AC has been working ON and OFF at cooler days before
1/ Now it works only when leaving the car overnight,
2/ But, AC works ice cold at 1st time ON Only, if turning Off and On again, it will not work.
Checked without error code. ( pressure 5 bar when running ice cold, 8.5–9 bar when not)
Tried adding diode but no help
Any ideas!!!
1/ Now it works only when leaving the car overnight,
2/ But, AC works ice cold at 1st time ON Only, if turning Off and On again, it will not work.
Checked without error code. ( pressure 5 bar when running ice cold, 8.5–9 bar when not)
Tried adding diode but no help
Any ideas!!!
Newbie
Joined: May 2019
Posts: 5
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2012 gl350
EmilyMB... Any more info on this? Is the compressor solenoid removable from the compressor, or did you replace the entire part? Many thanks for posting up your solution.
Member
Joined: Jul 2010
Posts: 131
Likes: 24
gl550
Solenoid is replaceable, but you need to get the right one for your compressor. (Amazon has it around $25-30)…i tried to replace it without removing the compressor, make sure all pressure must be released.( not much room to do) . I recommend to replace the new compressor if your is 6+ yr old.
Newbie
Joined: May 2019
Posts: 5
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2012 gl350
Solenoid is replaceable, but you need to get the right one for your compressor. (Amazon has it around $25-30)…i tried to replace it without removing the compressor, make sure all pressure must be released.( not much room to do) . I recommend to replace the new compressor if your is 6+ yr old.
Yes... if I am to release the pressure... easy to do the compressor swap. Lots of compressors available for decent prices.
Cheers
(for those who are interested... I had the same symptoms, did the diode thing... and still no dice. checked fan relays, fan function, and confirmed power to compressor and same issues. so I'm pretty sure it's time for a new solenoid/compressor. Will swap out entire compressor assembly.)
