RE: ac wont shut off - thanks and another question

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

... I've experienced a very similar effect in American cars I've driven too
... I don't have any experience on other European or Asian marques ... I've
never really thought that much of it ... you've got to expect some effect
when you insert and remove such a high engine load from the system.  

One of the things I read in one of the Audi Service Training books I got
recently was that in 1989 was that they incorporated a new model compressor
clutch relay.  Page 32 of the book "1989 Model Change Information"
(WSP-521-180-00) states ... "As of 1989 MY, all Audi models will have a new
compressor clutch control relay.  The relay is installed to delay power to
the compressor clutch for 100 milliseconds.  This allows the compressor 'on'
signal to go to the fuel injection ECU first and increase the engine speed.
The result is smoother cycling of the A/C clutch."  The new part on the
diagram is given as 443 919 578E and it gives the wiring connections for
this module.  The thing it does not do is to compare the connectors and
wiring of the old module to indicate whether it is PnP or if some other
change is required.  I've been planning to look into this for inclusion on
my '88 5kCSQA ...

HTH!
Steve Buchholz
San Jose, CA (USA)

> ----------
> From: 	Mohammed Bhatti[SMTP:Mohammed.Bhatti@wcom.com]
> Sent: 	Tuesday, June 01, 1999 1:32 PM
> To: 	Ian Duff (UltraNet)
> Cc: 	quattro@audifans.com
> Subject: 	RE: ac wont shut off - thanks and another question
> 
> Ian,
> 
> Thanks for the info.  That's exactly what's happening.  So this is
> normal?  Funny, because this is the first time I've encountered this
> behavior, although admittedly, the other cars weren't Audi's.
> 
> mkb
> 88 80q
> 
> >>>>>>>>>>
> That clicking is your A/C compressor being told to compress by your A/C
> controller. It normally compresses for 5 seconds or so, then coasts for 10
> seconds or so, the compresses for 5 seconds or so, then, well, you get the
> picture. I bet you notice a deceleration every time it clicks, right? Try
> to see if your car accelerates about 5 seconds after it decelerates...
> -Ian Duff.
> 
> >>Another Question - List:
> >>While driving with the ac on, I hear intermittent clicking from relays
> >>beneath the drivers dash.  The clicking coincides with car jerking
> >>momentarily.  Annoying since this happens everytime a click ocurrs
> >>(about every 10-15 seconds).  I assume I have to replace one of these
> >>relays, but how can I tell which one since there are 3 of them?  Also,
> >>what does this relay do?
> 
> >>Thanks.
> 
> >>mkb
> >>88 80q
> 
> <<<<<<<<<<<
>