Remove the wedge was placed between defroster unit and at the bottom of its installation
compartment to secure the defroster unit during air distribution box installation.

40)

Connect the defroster A/C system hoses.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

25/35

Connect both A/C system hoses on the defroster expansion valve.

41)

Install the defroster expansion valve lower connections lock plate.
On the defroster expansion valve, install the lower connections lock plate on the expansion
valve. Note: Tighten the connections lock plate fixing screw firmly.

42)

Tighten the defroster A/C system hoses connections.
On the defroster expansion valve, tighten both A/C system hoses connections nuts. Note:
Tighten the A/C system hoses connection nuts firmly.

43)

Close the flux valve for driver area heating system circuit.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

26/35

Close the driver area heater flux valve to maximize the flow through the defroster heating
circuit when purging.

44)

Start the engine and increase the engine idle speed to 1500 rpm in order to perform the
defroster heating system bleeding.

45)

Turn ON the climate system by turning the air director knob so that it points up to the deicing position, in this position the heater valve is fully open which simplifies purging.

46)

Bleed the defroster heating system.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

27/35

In the defroster unit at the heater coil, open the purging nipple to bleed the air from the
defroster heating system.
Close it when coolant free of air comes from the nipple.
Note: Place a tray for collecting the coolant drained.

47)

Check the coolant level. Add coolant if necessary.
Check the coolant fluid level in the expansion tank. Note: Fill up coolant fluid if necessary.

48)

Shut off the engine.

49)

Plug the defroster unit electrical harnesses.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

28/35

Plug the defroster unit electrical harnesses on the evaporator flap electric motor and
temperature sensor. Note: Put a new cable ties as required to fix the defroster electrical
harness to the defroster compartment.

50)

Open the flux valve for driver area heating system circuit.

51)

Perform the A/C system refrigerant filling.
Using a complete refrigeration equipment, proceed to perform the refrigerant filling process
for commissioning the entire vehicle A/C system.
Perform previously a sweep A/C system using nitrogen and vacuum the entire system.
Note: Avoid discharging refrigerant into the environment during filling process activities.
These types of practices are penalized according to the laws that apply in each country.
For more information about refrigerant air conditioning system filling, see the following
service information: 87001-3 Refrigerant air conditioning system, fill.
CAUTION: Wear appropriate protective equipment (mandatory nitrile goggles and gloves)
during the entire procedure. Failure to do this can result in personal injuries occasioned by
chemical burns by refrigerant at pressure and high temperature.

Writer: RCB Mex

Warranty Bulletin

52)

Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

29/35

Start the engine.
Start the engine and increase the engine idle speed to 1500 rpm to perform the A/C system
refrigerant filling.

53)

Turn ON the climate system by turning the air director knob so that it points up to the driver
position. Also, turning the temperature set knob at 64 °F (18 °C), the evaporator valve is fully
open which simplifies performing the A/C system refrigerant filling.

54)

Check the defroster A/C system refrigerant leakages.
Check the refrigerant leakages on the defroster expansion valve connections (hoses and
pipes).
Note: detect any presence of refrigerant leakages on the defroster expansion valve
connections, repair immediately if necessary.

Writer: RCB Mex

Warranty Bulletin
55)

Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

30/35

Check the defroster proper operation.
Check the defroster cooling proper operation on the driver area.
To check the defroster heating proper operation, perform the following steps:
- Turn ON the climate system by turning the air director knob so that it points up to the deicing position (in this position the heater valve is fully open).
- Check the defroster heating proper operation.
- Also check that heat is available in all circuits of the passenger's compartment.

56)

Turn OFF the climate system.

57)

Turn OFF the vehicle.

58)

Install the defroster compartment front cover plate.
Install the defroster compartment front cover plate by hooking the locking pins that secure
the cover at both sides to the defroster unit compartment.

59)

Close the front hatch.

Writer: RCB Mex

Warranty Bulletin

60)

Close the engine compartment.

61)

Install the guide panel.

Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

31/35

Install the guide panel on the dashboard assembly by screwing its fixing screws. Note:
Tighten the guide panel fixing screws firmly.

62)

Install the dashboard molding.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

32/35

Install the dashboard molding placed at the joint of the guide panel with the dashboard upper
cover panel. Note: For molding install, slide it down to pin molding on its fixations.

63)

Install the fire extinguisher.

64)

Reinstall the dashboard cover.
Install dashboard upper cover by screwing its 8 fixing screws placed around at the cover
contour. Note: Tighten the dashboard upper cover fixing screws firmly.

65)

Install the windshield. Refer to 8431-03-02-01 Windshield, Replacement in Impact if needed.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

33/35

Install the windshields on the vehicle, according to service operation: 84302-2 Windscreen,
replace. Note: Replace the windshields sealing molding with a new one.

Replace the windshield glass only if cracked

66)

Install the wiper arms. Refer to 3637-03-02-03 Windscreen Wiper Linkage, Replacement
in Impact if needed.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

34/35

Install the wiper arms. See the service operation 36384-2 Windscreen wiper arm, replace as a
reference. Note: For correct installation position, there must be 102 +/-13 mm (A) between the
windshield center pillar and the wiper blade center (this is for both wiper arms).
Do not forget to install again the plastic caps that cover the wiper arms fixing nuts. These caps
are installed by a light hand pressure.
SPECIFICATIONS:
- Tighten the wiper arm fixing nuts, applying the following torque: 35 to 45 Nm.
- (A) Distance between the windshield pillar center to the wiper blade center is: 102 +/-13 mm.

Writer: RCB Mex

Warranty Bulletin
Date

Expiration

01.2023

01.2024

WB22-85
Group
843

No.

Page

01

35/35

PARTS / WASTE DISPOSAL
DO NOT RETURN THE REPLACED PARTS. Discard waste according to applicable environmental
regulations (Municipal/State [Prov.]/ Federal)

WARRANTY
This modification is covered by Prevost’s normal warranty. We will reimburse you the parts and 18 hour(s)
(18.0) of labor upon receipt of a warranty claim. Please submit claim via our Online Warranty System,
available at www.prevostcar.com (under Service \ Warranty section). Use Claim Type: “Bulletin/Recall” and
select ‘’Warranty Bulletin WB22-85".

OTHER
VBC Bulletin

S2871

Fail Code

18.06

Defect Code

09

Syst. Cond

B

Causal Part

21125654

Access all our Service Bulletins on

http://techpub.prevostcar.com/en/
or scan the QR-Code with your smart phone.
E-mail us at technicalpublications_prev@volvo.com and type “ADD”
in the subject to receive our warranty bulletins by e-mail.

Prevost/Volvo Bus engages in a continuous program of testing and evaluating to provide the best possible product. Prevost/Volvo
Bus, however, is not committed to, or liable for updating existing products.

Writer: RCB Mex