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Re: Thanks and a plea for more help.

Jim,  I had similar problems - it ended up being the multifunction doo dad
temp sensor.  Just pull the plug off and leave it off until you solve the
problem.  The sensor sends to the temp gauge and also tells the compressor
to shut up if it thinks the engine it overheating.  So just pull it off and
that is one less thing to troubleshoot.  With the plug off the compressor
will run if it is only the sensor that is faulty.  Next find the low
pressure switch. it is under the plastic cover above the firewall about one
foot in from the passenger side of the car mounted on to a freon line. 
Pull this plug and jumper a wire between the two connections.  This will
rule out the possibility of the low pressure switch being bad. Another
switch that I think probably gets overlooked is the one under tha gas
pedal.  When you mosh on the gas, the switch shuts off der compressor for
something like 12 seconds.  It may be jammed on or defective.  I have no
Bently but I would be glad to talk to you.

Scott McPherson

> From: Jim Chiodo <jchiodo@gfs.com>
> To: quattro@coimbra.ans.net
> Subject: Thanks and a plea for more help.
> Date: Tuesday, July 01, 1997 11:51 AM
> This is a continuing thread about the air conditioner in my
> 865k.  I have receieved many suggestions, but I would
> reallly like to talk directly with someone who has a bentley
> manual and wouldn't mind spending a few minutes with me. If
> someone is willing to spend some time on the phone, could he
> or she drop me an email and I will send back my home 800
> phone number.  I don't want the world to see it as there are
> some spammers out there that I'd just not call me and make
> it worse by my paying for the call.   
> I've had lots of ideas from many list users.  This group is
> great.  Once I get the air working on my 86 5000, I'll post
> a question about my 92 100CS.  In the meantime, I know lots
> of stuff that is not the cause of my non functioning air
> conditioner.  I am ready to get creative. 
> My thought was that pin 8 from the AC control head is
> supposed to get to that relay by a round about route through
> some sensors and stuff.  (This is per the guy from
> Autosport).  Actually tracing the wire path through
> connectors etc. would be a nightmare so I am thinking of
> running a wire directly to the relay.  Before I do this, I
> need to know if pin 8 specifically goes to relay 11, coil
> side.  Relay 11 is the one under the hood in the fuse box
> and referenced on the lid as "air conditioner relay".
> Snce I get confused about terminology, I also need to verify
> that the contol head is really the unit in the console with
> the auto, warmer, cooler buttons and digital read out as
> opposed to the gizmo box with hoses under and behind the
> glove box.  
> One thing I should note is that when I meter the relay
> socket with the relay out, ignition on and doing an on-off
> of the air, I see a small change in the resistance to
> ground.   I would expect it to drop to ground, completing a
> path for 12V through the coil.  That is not happening.
> This leads me to believe a transistor somewhere on the
> control head might not be turning on.  I remember this from
> many years ago in an electronics class.  I suppose i could
> go to radio shack and replace all the common transistors on
> the board, hoping to get the one that makes it work.  That
> seems drastic though and I might cause other problems.  An
> board schematic would be real nice to have too.
> What I can't accept is that there might be two problems. 
> >From a earlier suggestion, I know the temperature sensor is
> kaput.  Coolant was seeping through it and the wires were
> corroded off.  I haven't replaced it yet, but plan to. I
> don';t know if the relay path goes through here or not. I
> wish I knew difinitively the exact wire path for the signal
> from the control unit to the relay.  
> If anyone is reading this during the day and have the bently
> with you an alternative number would be 800-968-7500 (dial 1
> for an extension, mine is 7802)  this is my work #.
> Thanks in advance.