Servicing air conditioning and heating - engine compartment — VW

Notes:

Parts marked with * can only be serviced by specially-equipped service workshops, since refrigerant circuit must be evacuated beforehand with extraction station V.A.G 1691.
Before performing service requiring the opening of the refrigerant circuit, the system must be converted to refrigerant R134a:

=> Workshop Manual "Air conditioning - with refrigerant R12, 1974 ▸"

Dust and pollen filter
Removing => Page
80-1
, item -
4
-

Plenum chamber cover
Removing and installing => Page
80-1
, item -
3
-

Water drain valve
Behind bulkhead insulation
Removing and installing => Fig.
2

Heat exchanger and vacuum hose guide
Two-way valve for fresh/recirculating air flap -N63-
Open when electrically connected
Vacuum hose connection diagram => Page
87-31

Radiator fan control unit -J293-
Strip fuse -S88-, in radiator fan control unit -J293-
Note Part No.

Vacuum reservoir
Insertion depth for vacuum hose: 30 mm
Removing and installing => Fig.
5

Vacuum hose
Vacuum hose connection diagram => Page
87-31

Thermo switch for air conditioner cut-off -F163- and thermo switch for coolant fan, 3rd speed -F165-
Thermo switch for air conditioner cut-off -F163- only on vehicles with engine codes AAA or ABF
Thermo switch for coolant fan, 3rd speed -F165- only on vehicles with 3-speed fan motor
-F165- switch coolant fan: into 3rd speed as temperature increases (on at 112°C, off at 108°C).

-F163- switches off magnetic coupling -N25- at excessively high coolant temperature (off at 119°C, on at 112°C).
Removing and installing on vehicles with engine code AAA => Fig.
3
Removing and installing on vehicles with engine code ABF => Fig.
4

Condenser*
Pressure relief valve*
Checking => Fig.
5

Magnetic coupling -N25-*
Ambient temperature switch -F38-
Switches off magnetic coupling -N25- at low ambient temperature (off at 2°C, on at 7°C).
Removing andinstalling => Fig.
7

Air conditioner pressure switch -F129-
Checking => Fig.
8
Removing and installing:

Tightening torque 8 Nm
Renew O ring seal (note Part No.).

Fluid reservoir with drier*
Sight glass*
Evacuating and charging valve*
Expansion valve*
Checking of insulation piece for expansion valve => Fig.
1

Fig.1
Checking expansion valve insulation piece

1 -
Insulator
2 -
Expansion valve

The insulator prevents drop in air conditioner efficiency caused by increasing temperatures in the engine compartment.

Fig.2
Removing and installing water drain valve

1 -
Water drain valve
2 -
Bulkhead
3 -
Water drain pipe, on evaporator housing
4 -
Mounting plate

Install water drain valve with opening of lip seal facing downward.
Water drain valve must not be bonded with underbody protection.

Fig.3
Removing and installing thermo switch for air conditioner shut-off -F163- and thermo switch for coolant fan, 3rd speed -F165- on vehicles with engine code AAA

Notes:

Cooling system is pressurized when engine is warm. If necessary, release pressure before carrying out repairs.
Refill with coolant after installing thermo-switch.

1 -
Clip
2 -
Thermostat housing
3 -
O ring
4 -
Thermo switch -F163-/-F165-, brown
5 -
Temperature sender switch -G2-/-F87-, yellow
6 -
Coolant temperature sender -G62-, blue

Fig.4
Removing and installing thermo switch for air conditioner shut-off -F163- on vehicles with engine code ABF

Notes:

Cooling system is pressurized when engine is warm. If necessary, release pressure before carrying out repairs.
Refill with coolant after installing thermo-switch.

1 -
Clip
2 -
Connection
3 -
O ring
4 -
Air conditioner cut-off thermo switch -F163-
5 -
Connector

Fig.5
Checking pressure relief valve on compressor

Task: protects refrigerant circuit against excessive pressures
The pressure relief valve tell-tale indicates if valve has operated. An adhesive attached plate is pushed out.
In this case, take vehicle to specialist workshop.

Fig.6
Removing and installing vacuum reservoir

1 -
Plastic pipe
Installation depth: 30mm

2 -
Rubber seal
3 -
Vacuum reservoir
4 -
Nut
5 -
Wheel housing liner

Removing and installing wheel housing liner

=> General body repairs; Repair Group 66; Removing and installing wheel housing liner
General body repairs
Removing and installing wheel housing liner

Fig.7
Removing and installing ambient temperature switch -F38-

1 -
Hexagon bolt, M8
Torque setting 15 Nm

2 -
Ambient temperature switch bracket
3 -
Horn bracket
4 -
Plastic clip
5 -
Ambient temperature switch
6 -
Horn

Fig.8
Checking air conditioner pressure switch -F129-

Visual check: Ensure that O-ring 10.8 mm x 1.8 mm is seated in groove

Switch part between contacts -T4a/1- and -T4a/2- of connector housing switches magnetic coupling -N25- off when refrigerant circuit insufficiently filled or pressure too high.

Opens below 1.2 bar and closes again above 2.4 bar (switching threshold)
Opens above 32 bar and closes again below 24 bar (switching threshold)

Checking switch part:

Briefly bridge circuit between chambers 1 and 2 with engine running. If the magnetic coupling -N25- switches on, the refrigerant system is empty. Take vehicle to specialist service workshop.

Switch part between contacts -T4a/3- and -T4a/4- of connector housing switches coolant fan -V7- to 2nd speed when refrigerant pressure rises.

Closes above 16 bar and opens again below 12.5 bar (switching threshold)