Recirculating Air
12-31-2007, 06:25 AM
#1
Track Day
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Recirculating Air
Hi,
I have searched the forum for this subject but nothing seems to come up...
The recirculating air switch on my air con unit has not worked since I purchased my 993 Turbo five or so years ago. Having finally got a bit of spare time to investigate, I checked the valve under the front lid and noticed that one of the pipes had been blocked off - the one going to the white vacumn pipe which disappears into the loom and I think ends up under the dash.
I can hear the valve click when I push the switch in the car, but nothing seems to happen to the air flaps and I know my air is not recirculating as any external smell comes into the cabin regardless of the switch position.
I had read somewhere that this is a common problem, but can find a post either hear or on Pelican.
Any suggestions welcome.
Thanks and hope you all have a good new year!
Andre
I have searched the forum for this subject but nothing seems to come up...
The recirculating air switch on my air con unit has not worked since I purchased my 993 Turbo five or so years ago. Having finally got a bit of spare time to investigate, I checked the valve under the front lid and noticed that one of the pipes had been blocked off - the one going to the white vacumn pipe which disappears into the loom and I think ends up under the dash.
I can hear the valve click when I push the switch in the car, but nothing seems to happen to the air flaps and I know my air is not recirculating as any external smell comes into the cabin regardless of the switch position.
I had read somewhere that this is a common problem, but can find a post either hear or on Pelican.
Any suggestions welcome.
Thanks and hope you all have a good new year!
Andre
12-31-2007, 09:05 AM
#2
Drifting
Photo's...???
Andre - Can you post a few photos of the vacum lines in question under your front cowl area. There have been lot's of questions on previous threads about this. I have similar issues on my 95' 993 and I have posted photos before. I have a white line and a black line under my cowl area. The white line finishes in a junction block and the black line is just hanging out there so to speak. It does not finish anywhere...it just comes out of the wire bundle and looks like it should finish somewhere but does not. My finger is holding the tip of the black wire in the first photo and you can see the black line in wire bundle in the second photo. This situation may be perfectly ok though and my vacum leak might be elsewhere.
BTW: while you are at it, go ahead and 'join' the Rennlist. You are obviously a worthy 993 DIY'er.
mar
BTW: while you are at it, go ahead and 'join' the Rennlist. You are obviously a worthy 993 DIY'er.
mar
Hi,
I have searched the forum for this subject but nothing seems to come up...
The recirculating air switch on my air con unit has not worked since I purchased my 993 Turbo five or so years ago. Having finally got a bit of spare time to investigate, I checked the valve under the front lid and noticed that one of the pipes had been blocked off - the one going to the white vacumn pipe which disappears into the loom and I think ends up under the dash.
I can hear the valve click when I push the switch in the car, but nothing seems to happen to the air flaps and I know my air is not recirculating as any external smell comes into the cabin regardless of the switch position.
I had read somewhere that this is a common problem, but can find a post either hear or on Pelican.
Any suggestions welcome.
Thanks and hope you all have a good new year!
Andre
I have searched the forum for this subject but nothing seems to come up...
The recirculating air switch on my air con unit has not worked since I purchased my 993 Turbo five or so years ago. Having finally got a bit of spare time to investigate, I checked the valve under the front lid and noticed that one of the pipes had been blocked off - the one going to the white vacumn pipe which disappears into the loom and I think ends up under the dash.
I can hear the valve click when I push the switch in the car, but nothing seems to happen to the air flaps and I know my air is not recirculating as any external smell comes into the cabin regardless of the switch position.
I had read somewhere that this is a common problem, but can find a post either hear or on Pelican.
Any suggestions welcome.
Thanks and hope you all have a good new year!
Andre
12-31-2007, 09:29 AM
#3
hi,
the system is worked by vacuum from the engine I think. a vacuum line runs right from the back of the car to the area above the fuel tank to supply the necessary vacuum. You may need to check if this is connected. As yours is a TT, not sure where this runs to, but in a varioram car it runs to the intake manifold via various tubes. May be worth seeing if your vacuum pipes are still in order. Hope it helps.
the system is worked by vacuum from the engine I think. a vacuum line runs right from the back of the car to the area above the fuel tank to supply the necessary vacuum. You may need to check if this is connected. As yours is a TT, not sure where this runs to, but in a varioram car it runs to the intake manifold via various tubes. May be worth seeing if your vacuum pipes are still in order. Hope it helps.
12-31-2007, 10:15 AM
#4
Hi,
I have searched the forum for this subject but nothing seems to come up...
The recirculating air switch on my air con unit has not worked since I purchased my 993 Turbo five or so years ago. Having finally got a bit of spare time to investigate, I checked the valve under the front lid and noticed that one of the pipes had been blocked off - the one going to the white vacumn pipe which disappears into the loom and I think ends up under the dash.
I can hear the valve click when I push the switch in the car, but nothing seems to happen to the air flaps and I know my air is not recirculating as any external smell comes into the cabin regardless of the switch position.
I had read somewhere that this is a common problem, but can find a post either hear or on Pelican.
Any suggestions welcome.
Thanks and hope you all have a good new year!
Andre
I have searched the forum for this subject but nothing seems to come up...
The recirculating air switch on my air con unit has not worked since I purchased my 993 Turbo five or so years ago. Having finally got a bit of spare time to investigate, I checked the valve under the front lid and noticed that one of the pipes had been blocked off - the one going to the white vacumn pipe which disappears into the loom and I think ends up under the dash.
I can hear the valve click when I push the switch in the car, but nothing seems to happen to the air flaps and I know my air is not recirculating as any external smell comes into the cabin regardless of the switch position.
I had read somewhere that this is a common problem, but can find a post either hear or on Pelican.
Any suggestions welcome.
Thanks and hope you all have a good new year!
Andre
I think this is the part you need to replace. 993-624-325-00-M100 on pelican parts for $156.75
pain in the neck to replace. you should double check your fresh air vent servo motor by cycling on and off (recirc and vent) you should see the motor arm move... its electrically operated. mine was bad at 20,000 miles...
George
12-31-2007, 12:24 PM
#5
Andre
If the valve is clicking (actually an electrically operated vacuum switch), it is probably OK. The white pipe should be connected to it, as it operates the bypass air flaps inside the car. The black pipe should also be connected to the valve - this is the vacuum feed coming from the engine. With the engine running, pull the black pipe out of the rubber elbow and check there is vacuum present (tip of tongue works well here). If OK, make sure the vacuum is being transferred to the white pipe side of the valve when the recirculation button is pressed (not so easy to use the tongue method - maybe wet finger on rubber elbow will be enough). If you have correctly switching vacuum and no bypass air operation the best you can hope for is a disconnection further down the line, the worst is a failed air flap (never changed one but believe it is a major PITA).
Trev
If the valve is clicking (actually an electrically operated vacuum switch), it is probably OK. The white pipe should be connected to it, as it operates the bypass air flaps inside the car. The black pipe should also be connected to the valve - this is the vacuum feed coming from the engine. With the engine running, pull the black pipe out of the rubber elbow and check there is vacuum present (tip of tongue works well here). If OK, make sure the vacuum is being transferred to the white pipe side of the valve when the recirculation button is pressed (not so easy to use the tongue method - maybe wet finger on rubber elbow will be enough). If you have correctly switching vacuum and no bypass air operation the best you can hope for is a disconnection further down the line, the worst is a failed air flap (never changed one but believe it is a major PITA).
Trev
12-31-2007, 03:18 PM
#6
Track Day
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Hi, thanks for all your replies...
Mar, Some pics, the first shows the white pipe (which was disconected when I first investigated this issue, the rubber hose was plugged by what looked like a pukka porsche black trim screw!) this part is circled red and labelled 1. The black pipe is fitted to the other rubber hose.
BTW as I said before, recirculating the air has never worked and I got the car with 18,000 miles !!
I am dead sure this is a common problem.
Ok this pic shows where I think the white pipe goes, its under the dashboard on the drivers side (mine is RHD) Ive not looked yet but is this could be the part you recommend I should replace George?
Assuming the following photo is the fresh air vent actuator, this does not move when I press the recirculating air button, but does move when I push the full on air con button (big snowflake).
I will check the prescence of any vacumn as suggested by Trev.
Mar, Some pics, the first shows the white pipe (which was disconected when I first investigated this issue, the rubber hose was plugged by what looked like a pukka porsche black trim screw!) this part is circled red and labelled 1. The black pipe is fitted to the other rubber hose.
BTW as I said before, recirculating the air has never worked and I got the car with 18,000 miles !!
I am dead sure this is a common problem.
Ok this pic shows where I think the white pipe goes, its under the dashboard on the drivers side (mine is RHD) Ive not looked yet but is this could be the part you recommend I should replace George?
Assuming the following photo is the fresh air vent actuator, this does not move when I press the recirculating air button, but does move when I push the full on air con button (big snowflake).
I will check the prescence of any vacumn as suggested by Trev.
12-31-2007, 04:30 PM
#7
Drifting
Hmmm - I just had my wife run thru all the a/c and recirc switches: I can hear a little 'click' but I see no arms move - nothing moves in the cowl area at all!!?!?
Hi, thanks for all your replies...
Mar, Some pics, the first shows the white pipe (which was disconected when I first investigated this issue, the rubber hose was plugged by what looked like a pukka porsche black trim screw!) this part is circled red and labelled 1. The black pipe is fitted to the other rubber hose.
BTW as I said before, recirculating the air has never worked and I got the car with 18,000 miles !!
I am dead sure this is a common problem.
Ok this pic shows where I think the white pipe goes, its under the dashboard on the drivers side (mine is RHD) Ive not looked yet but is this could be the part you recommend I should replace George?
Assuming the following photo is the fresh air vent actuator, this does not move when I press the recirculating air button, but does move when I push the full on air con button (big snowflake).
I will check the prescence of any vacumn as suggested by Trev.
Mar, Some pics, the first shows the white pipe (which was disconected when I first investigated this issue, the rubber hose was plugged by what looked like a pukka porsche black trim screw!) this part is circled red and labelled 1. The black pipe is fitted to the other rubber hose.
BTW as I said before, recirculating the air has never worked and I got the car with 18,000 miles !!
I am dead sure this is a common problem.
Ok this pic shows where I think the white pipe goes, its under the dashboard on the drivers side (mine is RHD) Ive not looked yet but is this could be the part you recommend I should replace George?
Assuming the following photo is the fresh air vent actuator, this does not move when I press the recirculating air button, but does move when I push the full on air con button (big snowflake).
I will check the prescence of any vacumn as suggested by Trev.
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12-31-2007, 06:32 PM
#8
Track Day
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As usual nothing is straightforward with these cars!!
12-31-2007, 08:36 PM
#10
Drifting
There's absolutely nothing I can see to connect the loose black pipe to. My white and a black pipe are connected. But that 'loose' pipe doesn't intuitively go anywhwere?!?! We did not try the 'large' flake - duhhh! We'll try it Next Year!
Wonder if any other R-listers could help with looking at their setup?!?!
mar
Wonder if any other R-listers could help with looking at their setup?!?!
mar
01-01-2008, 09:51 AM
#11
Andre,
this tread is very helpful. The fresh air vent servo is what I am assuming you need to replace. If you put your recirc mode on, fan on hi and place piece of paper on the fresh air vent intake the paper should not be sucked onto the fresh air intake. if it does the fresh air flap is not closing all the way or stuck in the open position.
https://rennlist.com/forums/showthre...t=a%2Fc&page=2
this tread is very helpful. The fresh air vent servo is what I am assuming you need to replace. If you put your recirc mode on, fan on hi and place piece of paper on the fresh air vent intake the paper should not be sucked onto the fresh air intake. if it does the fresh air flap is not closing all the way or stuck in the open position.
https://rennlist.com/forums/showthre...t=a%2Fc&page=2
01-01-2008, 09:57 AM
#12
Andre,
in this pic... this is the air operated servo for the center vents??? I don't remember it that well... sorry. But, its recommended that you put a zip tie on the blue circle part as it can detach or loosen...
in this pic... this is the air operated servo for the center vents??? I don't remember it that well... sorry. But, its recommended that you put a zip tie on the blue circle part as it can detach or loosen...
01-02-2008, 07:03 PM
#14
Drifting
yes - the arm moves when the large flake is selected...
mar
mar
There's absolutely nothing I can see to connect the loose black pipe to. My white and a black pipe are connected. But that 'loose' pipe doesn't intuitively go anywhwere?!?! We did not try the 'large' flake - duhhh! We'll try it Next Year!
Wonder if any other R-listers could help with looking at their setup?!?!
mar
Wonder if any other R-listers could help with looking at their setup?!?!
mar
01-03-2008, 03:20 PM
#15
Intermediate
Andre-
I have had similar mysterious problems, but in my case I get no fresh-air via vents. Do you get fresh air all the time from outside? I also checked for clicking servo's, which worked, but I did not chase down all the same tests as described here. I will take a look later today or tomorrow and see what I can find.
My 96 C2 has 34k on it, and I did trace at least part of the problem to an actuator rod that connects to a flap under the dash. Mine has become detached, and I assumed this was probably the problem. It's so deep in there I can't reach it to re-attach it to determine if that is the issue or not- Instead I've been rolling down the windows! I guess what I am suggesting, without any reason but chance, is that you may have a similarly disconnected actuator rod. Worth a look. I will try to get under there with a camera and take a photo and also try to look at my lines. and let you know what I find.
One symptom is that I get this very odd "stale" smell whenever I turn on the heat or AC. I've grown to like it, a bit like Granny's attic. Well....maybe I don't like it that much. I've just convinced myself too....
Good Luck
G
I have had similar mysterious problems, but in my case I get no fresh-air via vents. Do you get fresh air all the time from outside? I also checked for clicking servo's, which worked, but I did not chase down all the same tests as described here. I will take a look later today or tomorrow and see what I can find.
My 96 C2 has 34k on it, and I did trace at least part of the problem to an actuator rod that connects to a flap under the dash. Mine has become detached, and I assumed this was probably the problem. It's so deep in there I can't reach it to re-attach it to determine if that is the issue or not- Instead I've been rolling down the windows! I guess what I am suggesting, without any reason but chance, is that you may have a similarly disconnected actuator rod. Worth a look. I will try to get under there with a camera and take a photo and also try to look at my lines. and let you know what I find.
One symptom is that I get this very odd "stale" smell whenever I turn on the heat or AC. I've grown to like it, a bit like Granny's attic. Well....maybe I don't like it that much. I've just convinced myself too....
Good Luck
G