General information about the heating system (VW Passat B3)

Contents: Additional equipment: electronic…↓ Air conditioning system with manual…↓

1 - water drainage casing
2 - suction pipe
3 - sealing gasket
4 - intermediate element

To replace, remove the instrument panel and heating system.

5 - heat exchanger
6 — air distributor housing
7 - air duct, main shut-off valve
8 - additional resistance

To replace, remove the glove box and shelf.

9 - fresh air fan

To replace, remove the bottom shelf.

10 — pedal cover
11 - footwell blower

To replace, remove the center console, instrument panel bracket and pedal cover.

12 — air duct casing
13 - heating system taps
14 — heating system control panel
15 — left air duct
16 — air distributor

To replace, remove the center console, bracket and instrument panel, heating system control and pedal cover.

17 — right air duct
18 — sealing gasket for air supply channel to footwell behind front seats
19 — air supply duct to the footwell behind the front seats
20 — blower

Fresh air for heating the car's interior is supplied by the heater fan. The air passes through the heater body and is directed to the corresponding air nozzles using various valves. If the heating system is turned on ("warm"), then cold air is directed through the heat exchanger. The heat exchanger is located in the heater body and is heated by hot liquid from the engine cooling system. The flowing air is heated by the hot plates of the heat exchanger and is then supplied to the interior of the car. The efficiency of heating is determined by the temperature of the incoming air. The air temperature, in turn, is regulated by the ratio of the mixed quantities of cold and hot air, which is determined by the temperature control valve.

[The original text is available on the portal vwmanual.ru]

The four-mode fresh air fan increases the heating system's capacity. Additional resistors are included so that the fan can rotate at different speeds in each mode. The resistors are located in the fan's connection socket. If a defect occurs, the connection socket must be replaced as a whole.

Additional equipment: electronic control of the heating system (Thermotronic)

Electronic control of the heating system can be installed as an additional equipment. In this case, the temperature inside the passenger compartment can be set, which is then quickly reached and maintained constant by electronic control of the temperature control valve. Two sensors for the air temperature in the passenger compartment (on the roof between the sun visors and in the driver's footwell), as well as an outside air temperature sensor (in the air intake pipe) transmit signals to the control unit, which is located behind the heating system drive. In accordance with these signals, the control unit controls the temperature control valve via the actuator motor.

Air conditioning system with manual or automatic control (Climatronic)

With the help of the air conditioning system, the temperature inside the cabin can be lowered below the outside air temperature. In addition, when the air conditioning system is operating, the humidity in the cabin decreases. The air conditioning compressor is driven by a V-belt from the engine crankshaft.