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

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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.

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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.

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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.

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