Volkswagen Golf / Golf GTI / Jetta. Manual - part 967

87-85

 

     High pressure sensor -G65-  

Where applicable, high pressure 
sensor -G65- -B-, transmits a square 
wave signal to Coolant Fan Control 
(FC) Module -J293- at a rate which 
varies according to the refrigerant 
system pressure. -J293 reacts to the 
pulse rate of the signal from -G65 as 
follows:  

On applicable engines, the signal 
generated by -G65- is also provided 
as an input to the Motronic Engine 
Control Module (ECM). As the 
amount of torque needed to drive the 
A/C compressor varies according to 
the refrigerant system pressure, the 
ECM processes this signal in order 
to enhance engine performance.  

Notes: 

 If the refrigerant system pressure 

rises, -J293- switches the 
radiator fan(s) to the second 
speed. 

 Where excessive or insufficient 

refrigerant system pressure is 
present (E.g.: insufficient air flow 
over condensor or when 
overcharged), -J293- switches 
A/C clutch -N25- off (-N25- 
controlled by -J293-). 

 On Climatronic equipped models 

it informs the A/C control head -
E87- that the pressure in the 
refrigerant system is OK and that 
A/C clutch -N25- can be switched 
on (-N25- controlled by -J293-). 

 The presence of -G65- is engine 

dependant. Where -G65- is not 
used, A/C pressure switch -
F129- is used instead 

 

Page 

87-84

 . 

 

Where -G65- is used, it's wiring 
circuit varies according to engine 

A/C refrigerant system

13/2/2005

application (E.g.: some are 
connected to the ECM, some are 
not). 

 Always confirm system use of -

G65- and applicable wiring circuit 
using applicable "Engine" and 
"Air conditioning" wiring 
diagrams. 

A/C refrigerant system

13/2/2005

87-86

 

  

   A/C system hoses and lines  

  

   The mixture of refrigerant oil (PAG oil) and 

refrigerant R-134a attacks some metals and 
alloys (for example, copper) and breaks down 
certain hose material. Use only factory specified 
replacement hoses and lines.  

  

   Hoses and lines are fastened together with 

threaded couplings/fittings and are retained (to 
bodywork or components) with specially isolated 
hose clamps.  

  

   Notes:  

  

  

 During servicing, all couplings, fittings and 

related fasteners must be torqued to 
specifications 

 

Page 87-89

 . 

  

  

 Ensure that only special tools (as specified) are 

used while servicing. 

A/C refrigerant system

13/2/2005

87-87

 

  

  

A/C refrigerant system, replacing 
components 

 

  

   Replacement A/C compressors, evaporators 

and condensers supplied by the Parts 
Department are filled with Nitrogen. If gas 
(Nitrogen) does not escape when the 
component is first opened, the component 
may be faulty (leaking) and must not be 
installed.  

  

   Replacement A/C compressors are filled 

with the total refrigerant oil quantity needed 
for the entire refrigerant system.  

  

   Always replace the receiver drier whenever 

the refrigerant system has been left open. 
Install immediately after opening to prevent 
moisture contamination of drier desiccant. 
Moreover, keep refrigerant system and other 
replacement components sealed for as long 
as possible to minimize the chance of dirt 
and moisture contamination.   

  

   Always plug open refrigerant line 

connections to prevent dirt and moisture 
contamination.  

  

   If the system has been discharged because 

of a damaged or leaking component 
(refrigerant hose/line, compressor, 
evaporator, condenser, etc.), flush the 
refrigerant system first with compressed air, 
then with Nitrogen (available locally) and 
collect the oil that runs out. This will remove 
the refrigerant oil which may be saturated 
with moisture.  

A/C refrigerant system

13/2/2005