PREVOST X3-45 Multiplex - Page 1153

Section 22: HEATING AND AIR CONDITIONING
PA1562
11
5.4 HVAC SYSTEM TROUBLESHOOTING
Problem/Symptom Probable Causes Actions
No temperature control in the
passenger area
Passenger temperature
display indicates two dashes
"--"
Problem with the temperature
sensor located in the evaporator
compartment air intake or the
sensor wiring
Instruct the driver to manually control the
temperature by playing with the passenger set
point. Set above 22°C (72°F) to heat and
below 22° C (72°F) to cool
Defroster fan not functioning
Module A47 is not powered or is
faulty
1. Check the SYSTEM DIAGNOSTIC menu
of the message center display (MCD).
Select FAULT DIAGNOSTIC and
ELECTRICAL SYSTEM. The message
“Voltage Module A47, Value too Low,
Active” confirms a power problem on the
module
2. Check / reset circuit breaker CB6
3. Check / replace fuse F5
4. Use the air release valves near the
entrance door and in the front service
compartment to lock / unlock the door
HVAC condenser fans not
functioning in speed 1
Circuit breaker CB7 was
manually tripped and not reset
Seized bearing
Brush problem
Bad wiring
Check / reset circuit breaker CB7
HVAC condenser fans not
functioning in speed 1
Module A54 is not powered or is
faulty
1. Check the SYSTEM DIAGNOSTIC menu
of the message center display (MCD).
Select FAULT DIAGNOSTIC and
ELECTRICAL SYSTEM. The message
“Voltage Module A54, Value too Low,
Active” confirms a power problem on the
module
2. Check / reset circuit breaker CB5
3. Check / replace fuse F67 , F68
HVAC condenser fans not
functioning in speed 2
Circuit breaker CB7 was
manually tripped and not reset
Seized bearing
Brush problem
Bad wiring
Check / reset circuit breaker CB7
Defroster fan is functioning
but no heat or cooling
available in the driver’s area
Module A46 is not powered or is
faulty
Faulty speed control
Bad wiring
1. Check the SYSTEM DIAGNOSTIC menu
of the message center display (MCD).
Select FAULT DIAGNOSTIC and
ELECTRICAL SYSTEM. The message
“Voltage Module A46, Value too Low,
Active” confirms a power problem on the
module.