[W126 Coupe] AC FAN- Related topic

[Axel Wulff]

Jay,

 

Judging from what you've written, I suspect your push-button unit is the source of your problems.

 

The heating and cooling system on our cars with the automatic climate control units have a "vacuum tree" wich controls all the valves that regulate the air flow to the vents. The vacuum tree is behind the vertical wood panel in the center of the dash on the passenger side. The vacuum tree is no the issue, it's the push-button unit that shuts and opens the lines.

 

Give Jonathan a call about remanufactured push-button units. If you can get them from the dealer, they'd be godawful expensive.

 

One thing you should check before you put a new push-button box in is the aux water pumps. The aux water pump sits between the firewalls, just below the monovalve. The aux water pump pumps the coolant from the engine through the heater core under the dash and it grounds through the push-button panel. If there is a short in the aux water pump, it can fry the push-button electronics.

 

Good luck.

Regards,
Axel J. Wulff
610-731-5453 Cellular
610-572-4611 Home



 


To: mbcoupes at mbcoupes.com
Date: Sat, 29 Aug 2009 11:25:22 -0400
From: johnjaykimrey1 at aol.com
Subject: Re: [W126 Coupe] AC FAN- Related topic


Axel,
Thanks for your response. 
 My SEC has 83k miles on it. I changed the monovalve( March 09) with new part before the start of the warm season so I don't think it is defective; however, I did not detemine the condition I had before replacing the old valve.I have assumed that the new valve is good(new part). Is there a check to determine if it is working correctly? 
 There are no over heating issues.
  I have an R12 system. It could be a little low on refrigerant but I added two 12 oz. cans of refrig. at the start of the warm season. I do know that the compressor is coming on and the input(pipe) at the low pressure side is getting very cold.I don't see any oil leaks around the compressor/seals and I get a release of gas when I press the valve on the low pressure side. The seals were changed by the previous owner at 60k. I thought this wasn't the culprit because of the mid vent throwing out ice cold air.
 I am concerned that you mentioned the Loss of vacuum because that may be consistent with the fact that the condition occurs without notice and me not touching the switches or temp control . By the way, I had the temp wheel in max a/c when this occurs.When I turn the wheel either way (max cool to max hot) no change.Where does does the vaccum originate from.
 Is there a check to detemine if there is a vacuum leak? I understand that this is a bear to fix if it is a vacuum leak  problem because of the air bags  so I would to like to be sure if  this is truly the problem.I will run some tests at the a/c control when it malfunctions again. I have a back up control box and I will change it to determine any change in situation.
 Thanks for your help,God knows I need it. The Summer isn't over in the South and I live in a small town where most mechanics are Ford and Chevy oriented only.
 Anone else have any thoughts on the matter. 
Jay

-----Original Message-----
From: Axel Wulff <axelwulff at hotmail.com>
To: mbcoupes at mbcoupes.com
Sent: Sat, Aug 29, 2009 8:42 am
Subject: Re: [W126 Coupe] AC FAN- Related topic




Jay,
 
I haven't seen your exact symptoms before, but you could have a number of issues, including bad monovalve, failing vacuum valves in the dash, low on refrigerant and failing AC push-button unit.
 
That you get both hot and cool air at the same time through different vents would indicate that the push-button unit is malfunctioning, but other sources of problems can't be excluded.
 
How many miles on the car? Any engine cooling issues (i.e. does the engine temp stay below 100)? Are you using R134 or R12 refrigerant? How's the refrigerant level? Have you changed the monovalve, or are you still running the original?
 
Try setting the temperature wheel to max hot and to max cool and check if the airflow is consistent hot and cold.

Good luck.

Regards,
Axel J. Wulff
610-731-5453 Cellular
610-572-4611 Home



 


To: mbcoupes at mbcoupes.com
Date: Fri, 28 Aug 2009 19:43:44 -0400
From: johnjaykimrey1 at aol.com
Subject: Re: [W126 Coupe] AC FAN- Related topic


Hi, 
My 89 sec with 83K miles is giving me an a/c problem and I need some direction as to where to start looking at the possible fix. It cools fine in the defrost, mid level and lower level for approximately 20  to 30 minutes then inadvertently the lower and windshield(defrost) goes to hot and I mean hot yet the mid level is cooling. I do not have to touch the climate controls to have this to happen. What are the most likely areas to look at. need some help very badly!!! any input is greatly appreciated. 
Jay Kimrey

-----Original Message-----
From: James Huntress <jhuntress at bellsouth.net>
To: 'Mercedes Coupes Mailing Lists' <mbcoupes at mbcoupes.com>
Sent: Fri, Aug 28, 2009 4:45 pm
Subject: Re: [W126 Coupe] AC FAN






The a/c fan blower fuse is here good luck. I just repaired mine. Jim


From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of kelly frink
Sent: Friday, August 28, 2009 4:56 PM
To: Mercedes Coupes Mailing Lists
Subject: [W126 Coupe] AC FAN
 
Hi All 

 

My AC fan stoped working today and it`s hot does anyone know if the fuse for the blower Motor is outside the fuse box or not

 

'Thanks Kelly
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