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