Air conditioning system - function check

AP83.00-T-8352CA

Air conditioning system - function check

14.1.05

 Danger!

Risk of accident caused by vehicle starting off by itself when engine is running. Risk of injury caused by contusions and burns during starting procedure or when working near engine

Secure vehicle to prevent it from moving.
Wear closed and snug-fitting work clothes.
Do not grasp hot or rotating parts.

AS00.00-Z-0005-01A

1

Start engine

 A minimum coolant temperature of
50 °C must be ensured.

2

Turn passenger compartment blower rotary switch (1) and driver area blower rotary switch (2) to stage 1

3

Press AC operation switch (6)

The AC indicator lamp (7) must light up.

It is only possible to check the function of the air conditioning for its cooling capacity if the temperature in the passenger compartment is above 17 °C.

Check refrigerant compressor

4

Turn passenger compartment temperature rotary switch (8) to maximum cooling capacity setting

5

Open rear engine flap

6

Carry out visual inspection of refrigerant compressor

 When the engine is running and the air conditioning is operating, the clutch hub (18) must rotate.

7

Close rear engine flap

Check condenser fans

 Danger!

Risk of death caused by falling from vehicle roof. Risk of injury to other persons caused by falling objects during work in roof area.

AS65.00-Z-0002-01A

8

Carry out visual inspection of condenser fans (arrows) on vehicle roof

 The condenser fans (arrows) must operate when the air conditioning is switched on.

Check air recirculation flap of front box

9

Hold a sheet of paper to the grille (9) and switch the fresh air mode switch (3) on and off



Fresh air mode:

 The paper must not be suctioned.

Air recirculation mode:

 The paper must be suctioned.

Check front box radial fans

10

Turn driver area blower rotary switch (2) from stage 1 to stage 2 and then to stage 3

 The blower output of the radial fan must increase noticeably.

Check front box heat output

11

Turn driver area temperature rotary switch (5) to maximum heat output setting

12

Check temperature of air flowing out in driver area

 The temperature of the air which flows out after approx. 3 minutes must be significantly higher than the outside temperature.



*WH58.30-Z-1002-08A

Check front box air distribution

13

Move driver area air distribution switch (4) to center position

 The air flow must flow out of the windshield and footwell ventilation air nozzles.

14

Move driver area air distribution switch (4) to stage 1

 The air flow must flow out of the windshield air nozzles.

15

Move driver area air distribution switch (4) to stage 2

 The air flow must flow out of the footwell ventilation air nozzles.

Check cooling capacity of passenger compartment climate control

16

Hold the sensor of the temperature measuring instrument in the air flow at the air nozzles (12) and measure the temperature of the air flowing out

 The temperature of the air which flows out after approx. 5 minutes must be significantly below the outside temperature.

If necessary check the air filters for passenger compartment ventilation for contamination and/or check the air conditioning system for leaks:



Air conditioning - cleaning the air filter for passenger compartment ventilation

AP83.30-T-8334CA



Inspect the refrigeration circuit for leaks.

AR83.30-T-1209-01C



*WH58.30-Z-1002-08A

Check passenger compartment recirculated air flaps

17

Move fresh air mode switch (3) to stage 1 for fresh air mode and check position of air flaps (10)

 The air flaps (10) must be closed but in this case the air filters for the passenger compartment ventilation are only partly visible.

If necessary detach the air recirculation grilles to check the position of the air flaps (10).

18

Move fresh air mode switch (3) to stage 0 for air recirculation mode and check position of air flaps (10)

 The air flaps (10) must be open and in this case the air filters for the passenger compartment ventilation are completely visible.

Check passenger compartment radial fans

19

Turn passenger compartment blower rotary switch (1) from stage 1 to stage 2 and then to stage 3

 The blower output of the radial fans must increase noticeably.

20

Close all open air nozzles (12) above seats in passenger compartment

21

Open one air nozzle (12) on the left and right side of the vehicle in the passenger compartment

22

Compare the air flows on the left and right side of the vehicle to each other

 If the force of the air flowing out of the open air nozzles (12) is uneven: 

Check function of radial fans on the weak side, replace if necessary:





Remove/install radial blower

AR83.20-T-3750CA

Check heat output of passenger compartment climate control

23

Turn passenger compartment temperature rotary switch (8) to maximum heat output setting

24

Hold the sensor of the temperature measuring instrument in the air flow at the open air nozzles (12) and measure the temperature of the air flowing out

 The temperature of the air which flows out after approx. 5 minutes must be significantly higher than the outside temperature.



*WH58.30-Z-1002-08A

Check heat output of convectors

25

Check temperature of convectors (11)

 The convectors (11) on the left and right side of the vehicle must warm up.



*WH58.30-Z-1002-08A

26

Turn off engine

Number

Designation

WH58.30-Z-1002-08A

Digital temperature measuring instrument (measuring range -20° to +70°)