993 AC problems
Thread Starter
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Joined: May 2009
Posts: 77
Likes: 1
993 AC problems
Here is the problem. With the AC on, cold air exits only the passenger side vents; warm air only out the far driver side vent near the driver's door even with AC at full blast. The air from the passenger door side vent is very cold, so I know the compressor is working well. Related problem is I cannot get cool air thru any of the vents without the AC switched on. So, with cool outside temps, even with the temp **** at full cool setting, I get warm air out the vents once the engine is warmed up. Car is a '97 993 w/54K miles. Any ideas? Thanks.
Racer
Joined: May 2005
Posts: 339
Likes: 1
From: Copperas Cove, TX
I have the same issue...hopefully someone will chime in with a solution, I have tried all the tests I have found usuing the search, the last thing which is the most expensive would be to replace the computer...I dont think it is the computer so I dont want to take that gamble. I wish there was a way to 100% identify the problem (as a do-it-yourselfer) without all the guessing.
Former Vendor
Joined: Apr 2010
Posts: 416
Likes: 90
There is an air flow control valve on both sides down by the footwell (the door jamb/sill area).
It may be sticking or has failed altogether. It is operated by electrical servo.
When the AC is on these should close to stop warm air from entering the cabin.
There is another thread on this here with pics (if I recall correctly). I am not on my shop PC right now but can post the PET diagram later if needed.
If the flaps are operating properly and the vacuum lines are connected then the CCU may be the issue... but hopefully not. They are $$$
With one side cold, one side hot, I'd lean towards the servo on the hot side.
MarkD
It may be sticking or has failed altogether. It is operated by electrical servo.
When the AC is on these should close to stop warm air from entering the cabin.
There is another thread on this here with pics (if I recall correctly). I am not on my shop PC right now but can post the PET diagram later if needed.
If the flaps are operating properly and the vacuum lines are connected then the CCU may be the issue... but hopefully not. They are $$$
With one side cold, one side hot, I'd lean towards the servo on the hot side.
MarkD
Last edited by FD Motorsports; Apr 23, 2010 at 11:45 AM.
Rennlist Member
Joined: Apr 2004
Posts: 2,570
Likes: 538
From: Oslo, Norway
Bobbyd, you have a faulty air vent servo. It's vent flap is stuck most likely to a elecrical failure inside the servo. Very common problem on 964 and 993. The servo units for controlling hot air are placed behind the carpet in the footwell on both sides.
Remove the carpet side wall to see it, it is mounted on the air hose. Part number is most probably 993 624 325 00.
There's tons of onfo on faulty air servos in this forum, but you can find more detailed info as well as pictures here: www.ccu.tore.bergvill.com
By the way, you have no vacuum problems, only the resirc flap is vacuum operated in the 993.
Best regards,
Tore
Remove the carpet side wall to see it, it is mounted on the air hose. Part number is most probably 993 624 325 00.
There's tons of onfo on faulty air servos in this forum, but you can find more detailed info as well as pictures here: www.ccu.tore.bergvill.com
By the way, you have no vacuum problems, only the resirc flap is vacuum operated in the 993.
Best regards,
Tore
Racer
Joined: May 2005
Posts: 339
Likes: 1
From: Copperas Cove, TX
i actually went home after work and immediately took apart the passenger side kick panel...the servo was in fact bad...the contacts were burnt...i took it off the flapper assembly and closed the flap...a/c blows ice cold on both sides now...i will replace the servo next fall when the weather cools off...this is a great site!
