Component Overview
Component Overview
• Servicing refrigerant circuit, refer to => [ Refrigerant Circuit, Servicing ] Refrigerant Circuit, Servicing.
• All work or components marked with 1) can be repaired, replaced or performed in any workshop (work that does not pertain to refrigerant circuit).
• All refrigerant circuit components not marked with 1) as well as all refrigerant hoses and refrigerant lines can only be serviced or replaced in a workshop equipped with the necessary tools and in which the work procedures are performed by qualified personnel (refrigerant circuit must be discharged).
• This illustration shows in one overview the various refrigerant circuit components, the exact arrangement inside the vehicle depends on version and engine.
HD = High-pressure end
ND = Low-pressure end
1 A/C Compressor Regulator Valve (N280)
• Checking activation and function, refer to => [ A/C Compressor Regulator Valve, Checking Activation Signal ] A/C Compressor Regulator Valve (N280), Checking Activation Signal 1).
2 Compressor
• Removing compressor from bracket and re-installing in vehicles with 6 cylinder engine, refer to => [ Compressor, Removing and Installing on Bracket ] Compressor, Removing and Installing on Bracket 1).
• On an 8 cylinder, it is necessary to evacuate the refrigerant circuit in order to remove the A/C compressor from the bracket. Refer to => [ Compressor ] Compressor.
• When installing refrigerant lines/hoses and pertaining bracket, make sure there is a sufficient gap between belt, bracket and belt pulley.
• Depending on time period of production and on engine, compressor construction type may vary. Refer to the Electronic Parts Catalog.
• At beginning of production, Denso compressors were installed.
• These compressors are available as replacement parts with different oil fill capacities, therefore note capacity on compressor and the exact part number. Refer to the Electronic Parts Catalog. The reason for the different oil capacities in the compressor for an otherwise identical refrigerant circuit lies in the design of the compressor itself, note these oil capacities. Too much oil in the circuit leads to higher pressures and reduces cooling performance of the system. Too little oil may lead to lubrication problems in the compressor.
• Depending on compressor type and design of refrigerant circuit (one or two evaporators), different refrigerant oil and refrigerant capacities are designated for the refrigerant circuit.
3 Compressor Belt Pulley/Drive Unit
• Different versions (depending on the engine). Refer to the Electronic Parts Catalog.
• A/C Compressor Belt Pulley, 6 Cylinder TDI, removing and installing 1); refer to => [ Compressor Belt Pulley ] Compressor Belt Pulley.
• For the correct ribbed belt allocation for 6 cylinder TDI, refer to the Electronic Parts Catalog.
• A/C Compressor Drive Unit, 8 cylinder FSI, removing and Installing, refer to => [ Compressor Drive Unit ] Description and Operation (A/C Compressor, removing, refer to => [ Compressor ] Compressor).
• An overload safeguard is installed between the belt pulley/drive unit and driveshaft, this protects the compressor belt/engine in the event that the compressor is seized or does not move freely.
• If compressor is runs with resistance, overload safeguard interrupts power transmission to compressor.
• Rubber elements are installed between belt pulley/drive unit and compressor driveshaft, vibrations which may occur during compressor operation may be dissipated via these rubber elements (damper function at torque fluctuations).
• Depending on compressor type, different belt pulleys are installed on compressor. Refer to => [ Compressor Belt Pulley ] Compressor Belt Pulley.
4 Oil Drain Plug
5 High Pressure Relief Valve
6 Connection Without Valve
7 Refrigerant Temperature Sensor (G454)
• The connection on which Refrigerant Temperature Sensor is installed does not possess a valve, therefore Refrigerant Temperature Sensor must only be removed with a discharged refrigerant circuit.
• Function and signal utilization, refer to => [ Refrigerant Temperature Sensor (G454), Function and Signal Utilization ] Refrigerant Temperature Sensor (G454), Function and Signal Utilization.
• Not installed in all vehicles (depends on the engine, the version of the vehicle and when the vehicle was produced).
• For example, installed in vehicles with a 6 cylinder TDI engine or an 8 cylinder engine through 10.2007.
• The refrigerant temperature sensor was discontinued as of November 2007 as a running change. On vehicles with the Comfort A/C system, make sure the Climatronic control module (J255) for the Comfort A/C system is installed. Vehicles with a 6 cylinder TDI engine or an 8 cylinder engine but without a refrigerant temperature sensor may only have the Comfort front control and display unit installed (part number 4L0 820 043, beginning with index letter K). Refer to the Electronic Parts Catalog.
• If the vehicle has the Basis A/C system without a refrigerant temperature sensor, and the sensor is being displayed as a fault, then perform an adaptation to the Basis front A/C control head. It is not necessary to perform this on the Comfort A/C system because it has different versions of the front A/C control head. On vehicles wit the Basis A/C system, "Guided Fault Finding" displays the fault missing refrigerant temperature sensor and the evaluating of the refrigerant temperature sensor switches off (by entering "adaptation") of the Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding".
8 Condenser
9 Fluid Reservoir With Dryer Cartridge
• The dryer cartridge may be removed only when the refrigerant circuit is empty.
• Fluid reservoir is a component of the condenser.
• Dryer cartridge can be replaced as an individual part.
10 Connection In Refrigerant Line
• Bolts of the connection points must only be loosened when refrigerant circuit has been discharged.
• Depending on the version of the vehicle and the engine, these connection points may be present at different locations on the refrigerant lines.
11 Service Connection
Service connections (connection is not equipped with a valve) or the valves installed in them must only be removed when refrigerant circuit has been discharged.
• High pressure side.
• Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics.
• Depending on engine version, it may be necessary to remove different components in order to be able to connect to service coupling of the service station.
12 Cap
• With seal
• Always screw on
13 Connection With Valve
• Different installation locations depending on version and engine of the vehicle.
14 High Pressure Sensor (G65) 1)
• Removing and installing, refer to => [ High Pressure Sensor (G65) ] High Pressure Sensor (G65).
• Checking signal, refer to => [ High Pressure Sensor, Checking Pressure Signal ] High Pressure Sensor (G65), Checking Pressure Signal.
15 Expansion Valve
• For evaporator in front heating & A/C unit (heating & A/C unit under instrument panel).
16 Evaporator
• Evaporator in front heating & A/C unit (under instrument panel).
• Removing and installing evaporator of front heating & A/C unit, refer to => [ Front Evaporator ] Front Evaporator.
17 Service Connection
Service connections (connection is not equipped with a valve) or the valves installed in them must only be removed when refrigerant circuit has been discharged.
• Low pressure side
• Different versions (with primary sealing valve or with Schrader valve) depending on refrigerant line, distinguishing characteristics.
• Depending on engine version, it may be necessary to remove components in order to be able to connect to service coupling of the service station.
18 Cap
• With seal
• Always screw on
19 Pre-volume
• Is a component of refrigerant line to compressor.
• Pressure fluctuations are damped in the pre-volume.
• Not installed in all vehicles (depending on the engine and on the version of the vehicle); refer to the Electronic Parts Catalog.
20 Connection Of Refrigerant Line To Evaporator In Rear Heating & A/C Unit
• The bolts of the connection point may only be loosened when the refrigerant circuit has been discharged.
• Only present on vehicles with a rear heating & A/C unit (optional equipment, installed under trim at left in luggage compartment).
• High pressure side
21 Connection In Refrigerant Line To Evaporator In Rear Heating & A/C Unit
• Bolts of the connection points must only be loosened when refrigerant circuit has been discharged.
• Only present in vehicles with a rear A/C unit (optional equipment).
22 Expansion Valve At Evaporator In Rear Heating & A/C Unit
• For evaporator in rear heating & A/C unit (installed under left side luggage compartment lining).
• Only present in vehicles with a rear A/C unit (optional equipment).
23 Evaporator In Rear Heating & A/C Unit
• Only present in vehicles with a rear A/C unit (optional equipment).
24 Connection Of Refrigerant Line To Evaporator In Rear Heating & A/C Unit
• The bolts of the connection point may only be loosened when the refrigerant circuit has been discharged.
• Only present in vehicles with a rear A/C unit (optional equipment).
• Low pressure side