Volkswagen Golf / Golf GTI / Jetta. Manual — part 972

87-100

A/C pressure switch -F129-, checking

Notes:

The presence of -F129- is engine dependant.

Where -F129- is not used, high pressure sensor
-G65- is used instead

Page 87-85

.

Always confirm system use of either -F129

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

The pressure switch can be removed without
discharging refrigerant system.

- Visually check that O-ring 10,8 mm x 1,8 mm is

positioned correctly in the groove.

Switch part between terminals 1 and 2 switches off

the A/C clutch -N25- when the system pressure is
too high or when there is not enough refrigerant in
the system .

Switch part between terminals 3 and 4 switches
coolant fan -V7- (via the coolant fan control module
-J293-) to the next higher fan speed when system
pressures increase.

Switch opens when the pressure is below 1.2

bar and closes again above 2.4 bar (switch
point).

Switch opens above 32 bar and closes again

below 24 bar (switch point).

Switch closes above 16 bar and opens again

below 12.5 bar (switch point).

A/C refrigerant system, servicing

13/2/2005

87-101

-F129- functional checks

To determine proper A/C system performance,

perform the following functional checks with the
switch installed and connected.

- With the engine running, briefly bridge terminal 1

and 2 of connector. If the A/C clutch -N25-
engages, the refrigerant circuit is empty.

- Check refrigerant capacity (fill). If system

pressure is too low (refrigerant leakage), -F129-
switches A/C clutch off.

- Check cooling fan function. When system

pressure increases, -F129- causes coolant fan -
V7- to switch to next higher fan speed.

- Check if A/C system switches off. At excessive

system pressures (e.g.: caused by high ambient
temperatures or if condensor is blocked), -F129-
switches A/C clutch off.

A/C refrigerant system, servicing

13/2/2005

87-102

High pressure sensor -G65-, checking

Notes:

The presence of -G65- is engine dependant.

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

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

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

Always confirm system use of either -G65- or -

F129- and applicable wiring circuit using
applicable "Engine" and "Air conditioning"
wiring diagrams.

A/C refrigerant system, servicing

13/2/2005

87-103

Special tools

and
equipment
required

VAG 1767

Ignition
tester

VAG

1594/A (or
C)
Connector
test set

VAG 1598

A Test box

Applicable

wiring
diagram

In cases

where
refrigerant
system may
need to be
recharged,
use Kent-
Moore
ACR4 (or
equivalent)
(VAG 1885
illustrated).

Where

neccessary:
VAG
1551/1552
Scan Tool

Optional:

VAS 5051
Vehicle
Diagnostic
Testing and
Information
System

A/C refrigerant system, servicing

13/2/2005