Fw: Strange behaviour from climate control

[Dag Bøsterud]

Will this explain the low fan speed as well?

/Dag

----- Original Message ----- 
From: Dr. Ian McArthur 
To: 'Dag Bøsterud' 
Sent: Friday, June 25, 2010 11:18 PM
Subject: RE: Strange behaviour from climate control


There are a number of pneumatic valves that control the routing of the air in the 5TQ's.  These are controlled by a set of electrically operated valves located behind the glove box.  If any of these valves fail the climate control goes into safe mode and (generally) routes all of the air to the windshield (defrost mode).

 

The Bentley manual explains all of this very clearly, but it is complicated.

 

The climate control has a trouble shooting function that diagnoses what is amiss if things are not working right.  This is also explained in the Bentley.

 

If you need parts these climate controls are out of GM Buicks or Cadillacs of the same vintage.

 

One quick remedy is to get in behind the glove box and whack the controller with a hefty screwdriver.  The pneumatic solenoids often get bits of grunge in them which causes them to stick.

 

If you need more help, get back to me.  I have fixed a bunch of these in my 3 1988 5TQ's and other Audis.

 

Ian

Water Valley Alberta Canada

-----Original Message-----
From: quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] On Behalf Of Dag Bøsterud
Sent: June 25, 2010 13:50 PM
To: quattro at audifans.com
Subject: Strange behaviour from climate control

 

The climate control in my 1990 Audi 100 TQ Sport started to act up today.

It was abot 74 F outside and the system was blowing cold out of the centre vents,

when it suddenly started to blow cold out of the top vents. Along with this, the fan

speed decreased. This lasted for a few seconds, and then everything went back to normal.

This happened one more time on by 45 minute trip.

 

Tonight when driving home it was raining heavily outside, and I pushed the HI-button.

Nothing happened. It seemed like the fan was running on 50% or something.

After setting the temperature to HI and LO a couple of times I got the fan to start

at full speed.

 

The fan, heater core and temperature regulater motor was replaced with brand new parts

(bought at Autohaus Arizona) about three months ago. There's no fault codes.

 

What can cause this funny behaviour?

 

/Dag

1990 Audi 100 TQ Sport Exklusiv

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