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  #1  
Old 08-10-2007, 02:47 AM
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94 e320 a/c please help

just bought it a few months ago to discover a/c problem ... i had a previous post where someone recommended to change the cabin filters ... which I did but unfortunately it didn't help ... i confirmed i have extremely low air flow ... compared to my uncle's 95 e320 ... there is a difference in air flow speed when i try minimum, auto, and maximum but not even close to half as strong as my uncle's .... the air is cold but even if i put my hand on the center vents i barely feel air flow ... from this extremely weak air flow ... i am about to take apart the dash but b4 i do n e suggestions? does it sound like some physical air duct has come loose? some sort of a/c system valve issue (that changes a/c speed while idling or full throttle for example and is stuck) in engine bay? control unit issue? a bad/weak blower motor? or? any help would be greatly appreciated
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  #2  
Old 08-10-2007, 07:29 AM
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Question whether the evaporator temperature sensor has failed leading to icing up of the evaporator. This results in almost complete failure of air flow, no matter how hard the fan is blowing, albeit what air there is will be very cold! It is a quick and cheap fix, especially compared to taking the dash out!
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  #3  
Old 08-10-2007, 09:01 AM
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Vacum

Hi,

It sounds like a vacum related issue. Those vents are operated by vacum actuators. Those actuators open a flap inside each vent to direct air flow. I think there are 6 actuatos and you need to remove the dash to replace the ones for the center vents and recirculation. If vacum or actuators fail, the flaps stay at they default position wich is closed for central vents, open for defroster, and no recirculation. You should be able to hear those actuators operating when you push the reciculation button or move the vents control. Use a flashlight to see inside the central vents and using a long screwdriver, try to push down the flap (bottom) inside the central vents and see if you get airflow.

That happend in my car and what I did was removing the central vents and insert a pice of wood to keep the flap open (I thought acuator has failed), but latter I found that the problem was a vacum line disconected under the hood. When I got the oil filter replaced, someone disconected a vacum hose located close to the filter (behind the engine, close to the firewall, M104 engine). Also, If you remove the passenger glove box or airbag (there is a safety procedure for airbags), you'll find a valve with lots of vacum hoses conected. That valve operates the vents actuators. You can check vacum there. Are other vacum operated accesories working? (lights level, rear headrest, etc).

Right now, most air must be flowing thru the defroster.

Do a search on vacum actuators.

I hope this helps.
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Old 08-17-2007, 12:49 AM
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sorry guys for not replying sooner ... thank you for your help! I will try to look this weekend and see what I can do ... I look into the center vents and see a flap open up when I turn the air on ... I want to try the vaccum thing first ... i will look by the oil filter to see if its the same situation and if everything looks ok i will remove the passenger air bag ... I read a post on the proper process
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  #5  
Old 08-17-2007, 12:54 AM
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rear headrests operate fine and so do power locks but the locks are probably seperate .... every few minutes while the a/c is on I hear a hissing for a few seconds don't know if that is some actuators trying to move/open
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Old 08-17-2007, 01:31 PM
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Quote:
Originally Posted by lafooy View Post
... I look into the center vents and see a flap open up when I turn the air on ... I want to try the vaccum thing first ...
I still think the problem is vacum related but there are some things to consider:

1. I think you are looking at the wrong flap inside the vents. There are 2 flaps inside each vent. One of them is manual, operated by the weel located in the midle of the centrla vents. The other one is operated by vacum actuator but it doesn't open up. It opens down. Try pushing down inside the vent's bottom with a long screwdriver.

2. Locks have an independent vacum circuit and pump. But if you rear headrest are operating normally, I don't think the vacum leak is inside the hood. Maybe the actuators are just bad and need to be replaced or maybe there is a vacum leak related to the actuators hoses or the valve behind the passenger airbag.

I hope this helps.
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Old 08-17-2007, 05:46 PM
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I rather doubt it's vacuum related. With how much force does it blow out the windshield vents when in defrost mode? No vacuum is required for defrost, that is the default mode for the vent system.

I suggest you learn about and chase down the blower motor and regulator. Both are under the hood. You need to remove the windshield wiper assembly to access the blower, instructions can be found on this site. The blower motor may be binding up due to wear and age, or the regulator may be failing to deliver full voltage to the blower.

- JimY
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  #8  
Old 08-18-2007, 07:14 AM
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I agree with jcyuhn

I just had a problem with my 94 E320 with the A/C , air system recently. I had a blower motor quit out on me. I mention this because I read in the wiki that if the motor got installed backwards the blades are spinning in the wrong direction and low air flow would result. I ask if you had a repair recently?

If the blower hasn't been re-installed perhaps it just died and needs to be changed out. Trust me pay the extra and get the Behr OEM model replacement with squirrel cages. Other than this more info needed such as , "does air blow through the defrost setting?"
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  #9  
Old 08-20-2007, 02:44 PM
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I will try to respond to as many as I can .... i do see the manual flap I can open with the wheel between the vents and the one that is operated by vacuum actuator that opens down when i turn the air on .... as for the defrost, i believe the air is the same speed as my a/c at the high setting ... i just went for a drive and tried defrost, it stays at the same speed no matter if i hit low, auto, or high ... i am not too thrillled with the loud noise the car makes when first putting the ignition in acc position (when about to start the car) ... it sounds like some flap/door is opening or closing with the climate control system ... I even recorded it with my phone and could post it if some one wants ... i think this is related to the problem along with that hissing i hear every few min while the a/c is on .... i don't have the repair history on the car but judging from the genius that ripped the whole buttom molding off the base of the windsheild (either to possibly replace the windshield or to get to the blower motor) , i wouldn't be surprised if the blower motor was in its place backwards ... from what i saw when i changed the cabin filters, someone has removed those panels before (screws are showing wear on some almost stripped)
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  #10  
Old 08-29-2007, 12:46 AM
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well thank you everybody for your help I just fixed the a/c today .... problem was that the previous owner had put the blower motor in backwards i took it out and just flipped it ... didn't mess with removeing squirel cages etc ... air is niceeeee ... http://www.peachparts.com/Wikka/W124BlowerMotor was also very helpful
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