Re: Electronic Climate Control

[Eddi Jew <jew@rysa.dtc.hp.com>]

Experiences from my '86 5000S- YMMV
My guess is that the vacuum motor for the center vent is not acuating
(not getting vacuum). The control unit that supplies it is located under
the dash near the glove box. Remove the tray under the glove box (and
maybe the glove box, too- I forgot). Follow the color-coded vacuum lines 
(red, yellow, green, blue, black) and you'll find it in the corner. 
The Bentley manual does a decent job of detailing this out. The box 
controls the "Bowden"(sp?) cable and flap that mixes the hot/cold air.

To test this guess of mine:
  Set temp to: A/C max, lowest temp (60 deg?)
  
  Check if the yellow and green lines have vacuum. This could be
  done in a couple of ways:

     yank the octopus (6-port vac line) connector off the control unit. 

     On the control unit side, see if ports 2(yellow) and 3(green) have
     vacuum (it should). I wear surgical gloves and see if the ports 
     pull on it. Be careful not to suck up anything that might plug it up.
     No vacuum here indicates control unit's solenoids are bad, or some
     other control signal not right or not getting to the unit. Time to
     follow the trouble-shooting flow chart in Bentley.

     If it is the control unit (what's its real name?), rebuilt units can
     come with/without the servo motor for yanking on that Bowden cable.
     Check the ads in European Car.

  The test below ensures the vacuum motors can operate the center vents:

     yank the octopus (6-port vac line) connector off the control unit. 

     On the "line side" (not the control unit side), use some tubing to
     route the vacuum supply line (black) to the yellow and green lines.
     If you have a hand-operated vacuum pump (an automotive diagnostic 
     tool), you can use that as a source of vacuum and most have a vacuum
     gauge- if there's a leak in the diaphram of the motor, you'll know.

     If the vacuum holds, air should be comming out of the front vents 
     now. If not, check for stuck linkages or flaps.

FWIW, we had our first hot days in the Bay Area this last weekend, so it
was the semi-annual time to manually redirect the vacuum from defrost mode
to A/C-in-my-face mode. My unit died awhile ago, maybe 'cause oil got 
into those vac lines. This time, I used an aquarium air distribution valve
(a three-valver) and labeled the lines. I was also thinking of replacing 
the solenoids with the industrial strength ones I'd seen at some of the 
surplus stores around here, but issues like current draw and vacuum 
bleed-off made me time out. I would like to spend some time modifying 
fun things.

-- Eddi

 > I have an 87 Audi 5000CS Turbo with the Electronic Climate Control.
 > The problem is that the only air (heat or air conditioning) comes out
 > at the top right near the winshield.  Nothing comes out of the front vents
 > Does anyone know the problem.  Do I have to replace the whole climate contro
 > l.  If so how much?  Thanks for any advice.
 > Jeff Waldman
 > jawaldma@mailbox.syr.edu