TqW A/C gremlins (longish post)

[fjbauer@dsavm.e-mail.com]

Frank J. Bauer                                                                  
dassault systemes of America     email:fjbauer@dsavm.e-mail.com                 
Subject: TqW A/C gremlins (longish post)                                        
i have an electrical problem with my A/C that i can't figure out.               
my 86 200TqW is a euro model so the A/C is the same as the 85 5KST.             
originally, i thought i had a bad voltage reg in the A/C programmer,            
since my test lamp was lighting for the 12V input but no 8V regulated           
output was being supplied to the control head.  after plugging in               
another programmer (thanks rob) and still getting no lights on the controls,    
i rechecked the wiring with a voltage meter and found that the "12V" supply     
was actually less than 10.5V.  after tracing wires and checking resistences     
and generally cussing a lot i finally found a connector that was apparently     
not rated for the full 30A that the fuse is rated.  for all the bentley-heads,  
i refer you to page 97.148, track 262 where the 2.5mm black and blue wire       
has a red connector T4h.  on one side of this connector is fuse 17 (30A).       
on the other side are two wires:                                                
- one goes to the aforementioned A/C programmer (which is mislabelled on        
  the schematic) and then on to the inside temp sensor suction fan.             
- the other wire goes to yellow connector T4c (which i never did find)          
  and from there to terminals B&D of the blower control unit as well as the     
  fresh air fan itself.                                                         
the reason that less than 12V are reaching the programmer is that the           
connector is reaching melting temps while the fan is operating, which has       
eventually degraded the connection.  by poking, scraping, cleaning and          
spraying i was able to get a good enough connection to get the A/C              
functioning again.  however, i am loathe to use the original connector as an    
inline fuse.  after 2-5 minutes of fan operation, i can feel heat in this       
connector.                                                                      
my problem is i don't know what to check next.  the bentley has the typical     
" if you don't get this and you don't get that, bow toward ingolstadt and       
replace this module " diagnostic procedure.  they don't tell you what to        
check when everything runs just fine until the gd thing melts the wiring and    
burns your ride to the ground!  obviously i am pulling some major current       
here but it's not a simple short or i'd blow a fuse.  i could hope that it's    
a simple screw/plug-in type of fix like a bad blower control module, but        
i'm afraid the blower itself might be heading south.  arggh!  i think stediric  
once posted a treatise entitled "how to replace your blower on the side of a    
freeway in a snowstorm with a ginsu knife, a #2 phillips and duct tape"         
(or something like that) so if anyone has a copy laying around, please e me     
since i may need it soon.  one additional piece of information is that i        
noticed an oily substance in the seals (arf) where the front footwell air       
ducts (quack) attach to the air box.  as you can tell by now, all this time     
spent with my feet out the sunroof and my head under the dash has caused        
some (hopefully temporary) brain damage.  please help before i start thinking   
this is all normal behaviour (for me or the q.)                                 
tia...                                                                          
frank