PREVOST X3-45 COMMUTER User Manual

SECTION 22: HEATING AND AIR CONDITIONING
34
DOB 1300-1556 | X3-45 Commuter PA-1648 Maintenance Manual First release Oct 2020
5.7 HVAC ELECTRICAL SYSTEM TROUBLESHOOTING
Always check DID for electrical faults before performing repairs. Address any modules not
responding and take corrective action. This should be the first step in troubleshooting.
Problem/Symptom
Probable Causes
Actions
Defroster fan not functioning Module AE47 is not powered or
is faulty
Module AE24 is not powered or
is faulty
1. Check the Diagnostics menu of the Driver
Information Display (DID). Select Fault
Diagnostics and Electrical System. The
message “No Response ModAE47 (or
ModAE24), Active” indicates a power
problem on the module. (A CAN network
problem would show the same message
but doesn't produce these symptoms).
2. Check / reset circuit breaker CB1
3. Check CB16V (VECF)
4. Probe gray connector on module to see if
it is powered.
HVAC condenser fans not
functioning
Circuit breaker CB7 tripped
Seized bearing
Bad wiring
Module AE54 is not powered or
is faulty
1. Check / reset circuit breaker CB7
2. Check CB141, CB142, CB143, CB144 in
VECR.
3.
Check / replace condenser power relay
R10 (probe R10 coil power circuit 67A,
should be 24 volts).
4.
Check the Diagnostics menu of Driver
Information Display
(DID). Select Fault
Diagnostics and Electrical System. The
message “No Response ModAE54, Active”
indicates a power problem on the module.
(A CAN network problem would show the
same message but doesn't produce this
symptom).
5. Check CB5, CB67.
HVAC condenser fans not
functioning in speed 1
Module AE42 is not powered or
is faulty
1.
Check the Diagnostics menu of Driver
Information Display (DID). Select Fault
Diagnostics and Electrical System. The
message “No Response ModAE42,
Active” indicates a power problem on the
module. (A CAN network problem would
show the same message but doesn't
produce this symptom).
2.
Check / reset circuit breaker CB1, CB5,
CB7
3. Check CB67
4. Probe gray connector on module to see if
it is powered.

PREVOST X3-45 COMMUTER Specifications

General

Engine	Volvo D13
Transmission	Allison B500
Fuel Type	Diesel
Length	45 ft (13.7 m)
Width	102 in (2.6 m)
Horsepower	500 hp
GVWR	54, 000 lbs
Height	141 in