Re: AC Programmer Repair, On Board Computer & Cruise Control Failure (found)

[Tony Lum <tlum@flash.net>]

At 04:12 PM 11/2/97 -0500, you wrote:
>In a previous post I asked for help regarding a variety of problems.   My
>biggest problems were Air conditioning/ventilation system related.  I got
>some help, particularly some detailed instructions from Tony Lum, thanks
>Tony.  I followed up on the trouble shooting instructions and believe that
>I have a programmer with 3 of 4 solenmoids shot, but I want to make sure.
>
>I did check the self diagnostic mode and got a 00 reading (no fault).  I
>got a vacuum pump and trouble shot the vacuum lines.  No leaks.  pulling a
>15 in Hg vac on all lines caused the ventilation system to flow as it
>should.  I checked the programmer solenoids next.  I connected my pump in
>turn to each of the outgoing tubes from the solenoids.  On each of the red
>(recirc door), blue (floor-defrost), and green (bilevel) solenoids I
>couldn't develop any vacuum at all.  No slow leak, just a 0 reading on the
>gauge no matter how much I pumped.  The yellow (center vent) tube solenoid,
>pumped to 15 in Hg and held.  Curiously, my original problem is that I
>couldn't get ventilation from the center vents and that is the only
>functioning solenoid.  

It is the center tubes leading from the black vacuum lead that need to hold
vacuum.  If they leak when NOT selected then they'll bleed off enough
vacuum so that the one that should be engaged does not!  So disconnect the
center tubes and use the pump on the ones that are supposed to be off.
This is difficult in the car.  I took mine out off the car and unsoldered
them from the pc board and applied 12 volts directly to the coil to test.

>
>I would like to know how to fix the programmer, or am I better off getting
>a new one? 

Used they're about $125 with no guarantee they'll work (same shape as yours
probably). I wouldn't even think about new, unless the controller is
totally dead.

> I have heard about replacing solenoids, can they be bought by
>themselves? 

No. And don't even ask.  I got replacements by getting a junk controller
off an '85 5000. Even though the programmers are different, I got 4
solenoids and a working temp control motor off of it. Cost: $8.  Out of the
4, only 2 were functioning (funny the same 2 were bad in that controller
too).  Remember that GM cars use the same system if you dig through the
junkyard. Its best to go to a "Pick-and-Pull" yard that really can't
identify Audi parts. They seem to have no objection to stripping down an
assembly to get only what you want.  They only charge you for miscellaneous
heater parts and environmental charge only.

 Any instructions for soldering them back in given that they
>are partially plastic?

No.  Given a clean tip, soldering should be easy.  It helps if you use
acetone to dissolve the conformal coating on the pcb. If I ever figure a
way to repair the leaking solenoids, I'll post the info on the list.

>
>BTW I also had an inoperative cruise control system.  I found the casue of
>that.  There is a bundle of wires coming out of the stalk with the cruise
>control switches.  One was severed.  A simple splice will take care of it. 
>Wish all my problems were that easy.
>
>I still have an OBC problem.  It can't be set, adjusted, scrolled at all. 
>It's flat dead I checked the switch, but it's fine.  Any other trouble
>shooting suggestions?  

I'd try cleaning the contacts and rechecking ground connections.

>
>Thanks again.
>
>
Good Luck,

Tony (whose A/C works very nicely now)

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Tony Lum
Fremont, California, USA
mailto:tlum@flash.net

Audi Owner/Operator/Mechanic by Necessity ;-)

1987 5000CS Turbo Quattro
1985 4000CS Quattro
1980 5000S Sedan
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