W202 1997 C200 Air Conditioning System- Defrost Flaps

1993-Present: C200 CDI, C220 CDI, C270 CDI, C180, C200 Kompressor, C230 Kompressor, C220, C230, C280, C300 C350, CGI & CDI BlueEfficiency variants
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chopper0813
B Class
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Joined: Wed 15 Jul, 2015 4:58 pm
Model you own: w202
Location: Cairns. Qld.

W202 1997 C200 Air Conditioning System- Defrost Flaps

Post by chopper0813 » Thu 16 Jul, 2015 12:29 pm

Vacuum Diagram.png
Hi Folks,
About six months ago I purchased a 1997 W202 C200, the car was located in Sydney, I live in Cairns and so accepted remote engineering inspections. On receiving the vehicle, although the a/c system produced cold air, it only worked through the centre vents.
A closer inspection revealed that the outside temperature sensor had worn off by contact with the road and the coolant supply to the duo-valve had been blanked off.
The outside temperature sensor was replaced, the duo-valve serviced as both valves were stuck open. The air conditioner then seemed to function correctly with good temperature control.
Despite all efforts, there is a leak of defrost air to the defrost vents continuously. Using an endoscope through the defrost vents, the defrost flaps can be seen stuck slightly open and do not move with changes in the airflow switch. I have changed the climate controller but the results are the same.
Using a long grabbing tool through the top vents, the defrost flaps can be moved open and closed.
I believe the next step is to locate the vacuum valve block and test the defrost flap vacuum and electrical connections.
I just can't find the location of the vacuum valve block, I see on other forums that the LHD vehicles have it mounted on the blower case or behind the glove box.
Can somebody help me with its location?

Following all the diagnostic work above (Now 7th September) further examination of the EPC by VIN tells me the item I am searching for is a VALVE.
Item 5 on the EPC part No. A2028000278 or A2028000378. Confusingly, the EPC shows a LHD vehicle A/C system.
The EPC shows the VALVE positioned on the front face of the heater box, following a serious search I am still unable to physically locate it.
The page from the EPC is attached at the beginning of this post, hopefully some knowledgeable person will be able to help me solve this problem.
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Tenorite_320
C Class
Posts: 39
Joined: Tue 01 Sep, 2009 1:04 pm
Model you own: w204
Location: Balwyn, VIC 3103

Re: W202 1997 C200 Air Conditioning System- Defrost Flaps

Post by Tenorite_320 » Sun 16 Jul, 2017 12:21 am

Hi Chopper,

I have been researching a similar problem on my W202 280 Sport with virtually no air flow to the front windscreen with heater controls in the demist position - did you find a solution to this problem?
David

W202 - 1998 C200 Elegance: 5sp auto, brilliant silver, anthracite cloth (sold but remains in the family).
W163 - 2003 ML270cdi Luxury: 5sp auto, green black, orion grey leather (sold).
W204 - 2008 C320cdi: 7sp auto, tenorite grey, black leather.
W201 - 1992 190E-2.3 Sportline: 4sp auto, almandine red, mushroom cloth (sold).
W202 - 1998 C280 Sport: 5sp auto, brilliant silver, black leather
981 - 2014 Porsche Cayman S, DSG, white, blue leather

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Tony From West Oz
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Joined: Mon 20 Jun, 2005 10:04 pm
Model you own: w202
Location: Bedfordale WA

Re: W202 1997 C200 Air Conditioning System- Defrost Flaps

Post by Tony From West Oz » Sun 16 Jul, 2017 3:03 am

WHOA. Do not buy anything or muck around at this stage. The issue is most likely to be a simple mechanical disconnect.
Step 1. Remove the fascia from the HVAC controls, radio, etc.
Step 2. Remove radio. Feel up behind RHS of heater controls via radio opening. Are both linkages attached to the air box? If one or both of these is not connected, the air distribution control will not work correctly. If this is the case, continue:
Step 3. Remove HVAC controls
With HVAC Controls removed, align the air distribution knob so that the linkage sockets are aligned with the orientation of the air box linkage plugs.
Replace HVAC Controls, using a hand up the radio opening to help the linkages mate correctly. It is fiddly, but it helps to get it back together.

Step 4. Before replacing the radio and screwing everything up again, test the airflow control to ensure that it sends air where directed.
Once all working correctly:
Step 5. Reinstall radio and replace all screws
Step 6. Replace the fascia.

Drive and enjoy the HVAC, as it should work.

How do I know the above?
I needed to replace the globes in the HVAC controls and managed to not mate the linkages. Live and learn!
Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

'83 W123 300D 325000km (Wife's car Josephine - sold).
'84 W123 300D replaced good OM617 912 with OM617 952 and enjoyed having good acceleration for the first time since first driving a 300D in 2002 - became engine and trans donor for 300CD Turbodiesel conversion. Now parted out.
'86 W124 300D sold (Wife's old car - sold )
'85 W123 300CD, 275 000km (Fatmobile) rebuilt turbodiesel from previous Fatmobile transplanted into 280CE (occasional tourer)
'99 W202 C250 Turbodiesel (my darling Wife's car - Sold)
'98 W202 C250 Turbodiesel (my car - Sold)
'06 Ssanyong Musso Crew Cab 2WD Ute (OM662 diesel and Auto Transmission)

chopper0813
B Class
Posts: 21
Joined: Wed 15 Jul, 2015 4:58 pm
Model you own: w202
Location: Cairns. Qld.

Re: W202 1997 C200 Air Conditioning System- Defrost Flaps

Post by chopper0813 » Sun 16 Jul, 2017 11:08 am

Hi Folks,
My problem in fixing the defrost air leak was that I wrongly utilised the vacuum control information for the automatic climate control unit, most of which applies to LHD vehicles. Some time later I understood that the air control flaps (with the exception of fresh air) are moved manually. As Tony says, unless the operating spigots are connected correctly to the air box levers, nothing happens.
To fix my defrost air problem I needed to replace the RH flap operating lever as it had broken off.
Below is the post detailing my work in fixing the problem

viewtopic.php?f=26&t=21759

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Ivanerrol
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Model you own: w204
Location: Melbourne

Re: W202 1997 C200 Air Conditioning System- Defrost Flaps

Post by Ivanerrol » Sun 16 Jul, 2017 1:39 pm

For other air circulation problems.
This is the vacuum distributor in the earlier W202's
AC compressor rings.JPG
Note the green line - it's broken off. The circulation wont work properly

Here's another controller. It's underneath the glove box in front of the fan
AC controller.jpg
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Tenorite_320
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Joined: Tue 01 Sep, 2009 1:04 pm
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Re: W202 1997 C200 Air Conditioning System- Defrost Flaps

Post by Tenorite_320 » Sun 23 Jul, 2017 1:47 pm

Appreciate the comprehensive replies - with the radio and HVAC control unit removed this morning, I could manually operate the air distribution controls using a screw driver and the air flow was definitely alternating between the screen and the face/foot level vents. On that basis, it appeared the vacuum controls were operating correctly. A bit more sitting there looking at the problem and determined the control knob for air distribution in the HVAC control unit was upside down - rotated it 180 degrees and it works perfectly. Thanks again.
David

W202 - 1998 C200 Elegance: 5sp auto, brilliant silver, anthracite cloth (sold but remains in the family).
W163 - 2003 ML270cdi Luxury: 5sp auto, green black, orion grey leather (sold).
W204 - 2008 C320cdi: 7sp auto, tenorite grey, black leather.
W201 - 1992 190E-2.3 Sportline: 4sp auto, almandine red, mushroom cloth (sold).
W202 - 1998 C280 Sport: 5sp auto, brilliant silver, black leather
981 - 2014 Porsche Cayman S, DSG, white, blue leather

User avatar
Tony From West Oz
OZBENZ moderator
Posts: 3094
Joined: Mon 20 Jun, 2005 10:04 pm
Model you own: w202
Location: Bedfordale WA

Re: W202 1997 C200 Air Conditioning System- Defrost Flaps

Post by Tony From West Oz » Sun 23 Jul, 2017 2:50 pm

Happy to help you.
I was having problems like yours after replacing light globes in the HVAC control panel. Then the demist stopped working, it was easy to identify the cause.
Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

'83 W123 300D 325000km (Wife's car Josephine - sold).
'84 W123 300D replaced good OM617 912 with OM617 952 and enjoyed having good acceleration for the first time since first driving a 300D in 2002 - became engine and trans donor for 300CD Turbodiesel conversion. Now parted out.
'86 W124 300D sold (Wife's old car - sold )
'85 W123 300CD, 275 000km (Fatmobile) rebuilt turbodiesel from previous Fatmobile transplanted into 280CE (occasional tourer)
'99 W202 C250 Turbodiesel (my darling Wife's car - Sold)
'98 W202 C250 Turbodiesel (my car - Sold)
'06 Ssanyong Musso Crew Cab 2WD Ute (OM662 diesel and Auto Transmission)

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