Volkswagen Golf / Golf GTI / Jetta. Manual — part 1001

Note:

- Switch pressures, removing and installing switches as
well as switch arrangement and version, refer to vehicle
specific refrigerant circuit.

Repair Manual, Heating & Air Conditioning, Repair

Group 87 ,

A/C Refrigerant High Pressure Switch F23

Function:

Switches coolant fan to next higher stage upon pressure
increase in refrigerant circuit (approx. 16 bar).

A/C Refrigerant High Pressure Switch F118

Function:

Switches off A/C compressor when there is excessive
pressure in the refrigerant circuit (approx. 32 bar).

A/C Refrigerant Low Pressure Switch F73

Function:

Switches off A/C compressor when pressure drops in the
refrigerant circuit (approx. 2 bar).

Connections with valve for switches on
refrigerant circuit

Warning!

There is a danger of ice-up.

Refrigerant may leak out if refrigerant circuit is not
discharged.

Refrigerant must be extracted before removing valve -
C - .

General information on refrigerant circuit

13/2/2005

- Different threads for switch on high pressure and low
pressure sides.

- Only valves and O-ring seals that are resistant to
refrigerant R134a and refrigerant oil must be installed.

A - Connection (soldered in)

B - O-ring seal

C - Valve (with O-ring seal)

A/C Pressure Switch F129

This pressure switch has 3 functions:

1. Switches coolant fan to next higher stage upon pressure
increase in refrigerant circuit (approx. 16 bar).

2. Switches off A/C system if pressure is excessive
(approx. 32 bar), e.g. because of insufficient engine
cooling.

3. Switches off A/C system if pressure is insufficient
(approx. 2 bar), e.g. loss of refrigerant.

Note:

- A/C Pressure Switch F129 replaces the A/C Refrigerant
High Pressure Switch F23 , A/C Refrigerant Low Pressure
Switch F73 and the A/C Refrigerant High Pressure Switch
F118 .

High Pressure Sensor G65

This High Pressure Sensor G65 is installed instead of A/C
Pressure Switch F129 .

General information on refrigerant circuit

13/2/2005

When a voltage is applied, the high pressure sensor
generates a square wave signal or a data telegram. This
signal changes along with pressure in the system.

The downstream control modules (Coolant Fan Control
(FC) Control Module, Engine Control Module (ECM), A/C
Control Head E87 or Climatronic Control Module J255 ,
etc.) use this signal to calculate pressure in the refrigerant
circuit and accordingly to activate coolant fans and motor,
A/C Clutch N25 or to change activation of A/C Compressor
Regulator Valve N280 .

A/C Pressure/temperature Sensor G395

Warning!

There is a danger of ice-up.

Refrigerant may leak out if refrigerant circuit is not
discharged.

Refrigerant must be extracted before removing the A/C
Pressure/temperature Sensor G395 .

This A/C Pressure/temperature Sensor G395 is installed
instead of High Pressure Sensor G65 or A/C Pressure
Switch F129 .

The pressure signal is continuously checked, where the
temperature signal is only checked at temperatures above
0 C.

The Climatronic Control Module J255 operates with this
information and accordingly controls the coolant fans and
activation of the A/C Compressor Regulator Valve N280 .

General information on refrigerant circuit

13/2/2005

A/C Refrigerant Shut-Off Valve N43

The flow of refrigerant in the second evaporator is switched
on or off by the shut-off valve. It opens when voltage is
applied, switched by the A/C Programmer.

A/C Compressor Regulator Valve N280

The regulator valve is installed in the A/C compressor. It is
activated by the A/C Control Head E87 or the Climatronic
Control Module J255 . Pressure on the low pressure side is
influenced via the regulator valve and thus regulates the
temperature in the evaporator.

Note:

- A/C Compressor Regulator Valve N280 is a structural
component of the A/C compressor and cannot be replaced
separately.

Electrical components not installed on the
refrigerant circuit

A/C Programmer J127

This programmer switches off the refrigerant flow through
the 2nd evaporator when the temperature on the cooling
ribs of the 2nd evaporator sinks to the freezing point for

General information on refrigerant circuit

13/2/2005