[s-cars] AC compressor shuts off at 42 degrees F

[Tom Rodriguez]

I followed Stott's advice below and found the spring dangling from its lower anchor point in the center of the lower recirculation flap door.  Close inspection with a flash light revealed that the spring's upper anchor point (a small hole in the plastic bracket just below the servo) had failed.

To fix this I first removed the glove box and the plastic HVAC vent in the foot-well (the one that contains the foot-well light), and the lower recirculation flap door.  This gave me plenty of room to maneuver. Using some needle nose pliers and a bit of patience I was able to insert a length of stiff wire between the plastic bracket and the servo.  I positioned this wire adjacent to the broken upper anchor point, thereby creating a new upper anchor point at virtually the same location. I bent the ends of the wire around the plastic bracket to secure it in place.  Following reassembly I tested the recirculation flap door motion using the recirculation button on the HVAC control panel and it is now functioning perfectly.  Time: 2 hours including learning curve.  Cost: $0.

When the weather turns cold again I will report back on how this affects the problem of window fogging and the effectiveness of my defroster.  For now we are enjoying beautiful weather and low humidity here in Philadelphia, so I have no complaints!

Tom Rodriguez
'95 S6, 281K miles

-----Original Message-----
From: Stott Hare [mailto:stott at gwi.net] 
Sent: Thursday, November 9, 2017 7:07 PM
To: 'Tom Rodriguez' <trodri69 at gmail.com>
Subject: RE: [s-cars] AC compressor shuts off at 42 degrees F

Pretty sure you'll find that to be the problem.

Pull the lower trim under the glove box (with the footwell light), channel your inner contortionist, and look up behind the glovebox with a flashlight.  You should be able to find the recirc flap, and be able to determine if the spring is attached to the black plastic anchor point in the middle of the door.  I've had two failures there, one was the spring (often swinging by one end or loose in the bottom of the box there) and the other was a broken plastic anchor point.

 Scott Mockry's site still covers the similar issue on the type-44 chassis.
http://www.sjmautotechnik.com/trouble_shooting/ac.html#recirc

-Stott
-----Original Message-----
From: Tom Rodriguez [mailto:trodri69 at gmail.com] 
Sent: Thursday, November 9, 2017 5:37 PM
To: stott at gwi.net; s-car-list at audifans.com
Subject: RE: [s-cars] AC compressor shuts off at 42 degrees F

Thanks Stott. I will check on the recirc door/flap.  

I should also mention that the window fogging occurs as soon as the AC indicator light turns off (i.e. the little snowflake on the HVAC control panel on the dash), indicating that the AC compressor is no longer engaged.  If the compressor (and the indicator light) come back on, the windows clear up immediately.

Case in point - on Tuesday evening this week I drove for two hours in the rain.  During the drive the ambient outdoor temperature fluctuated between 39 and 43 degrees F.  Above 42 degrees F the AC compressor was on and the windows were clear.  Below 42 degrees F the AC compressor was off, the windows were foggy, and the air coming through the vents on the dash was noticeably more humid.  This fluctuated back and forth at least three times during the drive.

Based on this description, do you think the culprit is the recirc door/flap?  Might there be another cause?

Tom Rodriguez
'95 S6, 281K miles

-----Original Message-----
From: Stott Hare [mailto:stott at gwi.net] 
Sent: Thursday, November 9, 2017 1:33 PM
To: 'Tom Rodriguez' <trodri69 at gmail.com>; s-car-list at audifans.com
Subject: RE: [s-cars] AC compressor shuts off at 42 degrees F

Temp range sounds accurate, don't recall if it was 42 or 38 or something else, but know the compressor will no longer come on below a certain ambient.

What I would check is the return spring connected to the center of the recirc door/flap.  When that spring is missing, the flap door isn't returned to the proper position and fogging ensues.  Replacing it in my old 200 or S6A cured it for me.

-Stott

-----Original Message-----
From: S-CAR-List [mailto:s-car-list-bounces at audifans.com] On Behalf Of Tom Rodriguez
Sent: Thursday, November 9, 2017 12:31 PM
To: s-car-list at audifans.com
Subject: [s-cars] AC compressor shuts off at 42 degrees F

The AC compressor on my S6 shuts off at ambient air temperatures below 42 degrees F.  This causes the windows to fog up, particularly if it's raining out.  Cranking up the heat on the defroster only makes it worse since the hot air is humid and the windows are cold.

 

Any DIY suggestions to fix this?  And what is the minimum temperature supposed to be for the AC compressor to remain engaged?  I'm going to ask the Audi shop to fix this if I can't do it myself, but looking to save some $$.

 

Tom Rodriguez

'95 S6, 281K miles

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